Error 500 when trying to use the goodtable options

Hello,

I'm new to CKAN, so maybe I'm missing something on the config, but I'm unable to make even the sample README "id;group;measurement" to work.

I'm running CKAN 2.7.5 and downloaded the extensions from the branch master (both ckanext-validation.git and ckanext-scheming, the only issue I had was necessary to run `pip install six==1.11.0` before installing `ckanext-validation`)

I added the presets resource_schema, validation_options and hidden_in_form to /usr/lib/ckan/default/src/./ckanext-scheming/ckanext/scheming/presets.json
and my config looks like this:

```
scheming.dataset_schemas=ckanext.validation.examples:ckan_default_schema.json
scheming.presets = ckanext.scheming:presets.json

scheming.dataset_fallback = false

ckanext.validation.run_on_create_sync = True
ckanext.validation.run_on_update_sync = True

```

When I try to upload
```
<2 blank lines>
id;group;measurement
# 2017
1;A;23
2;B;24
# 2016
3;C;23
4;C;25
```

using no schema selected, and ```{
"headers": 3,
"delimiter": ";",
"skip_rows": ["#"],
"skip_checks": ["blank-rows"]
}```
as Validation options
I have an error 500, and the log goes as:

```Error - : 'NoneType' object has no attribute '__getitem__'
URL: http://fgv-ckan-aws.appcivico.com/dataset/new_resource/test-dt
File '/usr/lib/ckan/default/lib/python2.7/site-packages/weberror/errormiddleware.py', line 171 in __call__
app_iter = self.application(environ, sr_checker)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/dec.py', line 147 in __call__
resp = self.call_func(req, *args, **self.kwargs)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/dec.py', line 208 in call_func
return self.func(req, *args, **kwargs)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/fanstatic/publisher.py', line 234 in __call__
return request.get_response(self.app)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/request.py', line 1053 in get_response
application, catch_exc_info=False)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/request.py', line 1022 in call_application
app_iter = application(self.environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/dec.py', line 147 in __call__
resp = self.call_func(req, *args, **self.kwargs)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/dec.py', line 208 in call_func
return self.func(req, *args, **kwargs)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/fanstatic/injector.py', line 54 in __call__
response = request.get_response(self.app)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/request.py', line 1053 in get_response
application, catch_exc_info=False)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/request.py', line 1022 in call_application
app_iter = application(self.environ, start_response)
File '/usr/lib/ckan/default/src/ckan/ckan/config/middleware/pylons_app.py', line 268 in inner
result = application(environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/beaker/middleware.py', line 73 in __call__
return self.app(environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/beaker/middleware.py', line 156 in __call__
return self.wrap_app(environ, session_start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/routes/middleware.py', line 131 in __call__
response = self.app(environ, start_response)
File '/usr/lib/ckan/default/src/ckan/ckan/config/middleware/common_middleware.py', line 80 in __call__
return self.app(environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/wsgiapp.py', line 125 in __call__
response = self.dispatch(controller, environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/wsgiapp.py', line 324 in dispatch
return controller(environ, start_response)
File '/usr/lib/ckan/default/src/ckan/ckan/lib/base.py', line 212 in __call__
res = WSGIController.__call__(self, environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/controllers/core.py', line 221 in __call__
response = self._dispatch_call()
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/controllers/core.py', line 172 in _dispatch_call
response = self._inspect_call(func)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/controllers/core.py', line 107 in _inspect_call
result = self._perform_call(func, args)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/controllers/core.py', line 60 in _perform_call
return func(**args)
File '/usr/lib/ckan/default/src/ckan/ckan/controllers/package.py', line 681 in new_resource
get_action('resource_create')(context, data)
File '/usr/lib/ckan/default/src/ckan/ckan/logic/__init__.py', line 457 in wrapped
result = _action(context, data_dict, **kw)
File '/usr/lib/ckan/default/src/ckan/ckanext-validation/ckanext/validation/logic.py', line 489 in resource_create
resource_id, local_upload=is_local_upload, new_resource=True)
File '/usr/lib/ckan/default/src/ckan/ckanext-validation/ckanext/validation/logic.py', line 637 in _run_sync_validation
if not report['valid']:
TypeError: 'NoneType' object has no attribute '__getitem__'

```

I have another csv, using this schema: https://gist.githubusercontent.com/renatocron/7c84d31196a0a0da34fa8f9514253ac6/raw/df279c3b92cf7c19f376d1cb9143a54aa71a03f1/gistfile1.txt
and when I try the options `{ "skip_checks": ["blank-rows", "duplicate-headers"], "checks": ["sequential-value": {"column": "id"} ], "headers": 3}`
I also get an error 500, but with a different message:
```
Error - : Check "column" is not registered
URL: http://fgv-ckan-aws.appcivico.com/dataset/new_resource/test-dt
File '/usr/lib/ckan/default/lib/python2.7/site-packages/weberror/errormiddleware.py', line 171 in __call__
app_iter = self.application(environ, sr_checker)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/dec.py', line 147 in __call__
resp = self.call_func(req, *args, **self.kwargs)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/dec.py', line 208 in call_func
return self.func(req, *args, **kwargs)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/fanstatic/publisher.py', line 234 in __call__
return request.get_response(self.app)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/request.py', line 1053 in get_response
application, catch_exc_info=False)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/request.py', line 1022 in call_application
app_iter = application(self.environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/dec.py', line 147 in __call__
resp = self.call_func(req, *args, **self.kwargs)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/dec.py', line 208 in call_func
return self.func(req, *args, **kwargs)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/fanstatic/injector.py', line 54 in __call__
response = request.get_response(self.app)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/request.py', line 1053 in get_response
application, catch_exc_info=False)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/webob/request.py', line 1022 in call_application
app_iter = application(self.environ, start_response)
File '/usr/lib/ckan/default/src/ckan/ckan/config/middleware/pylons_app.py', line 268 in inner
result = application(environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/beaker/middleware.py', line 73 in __call__
return self.app(environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/beaker/middleware.py', line 156 in __call__
return self.wrap_app(environ, session_start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/routes/middleware.py', line 131 in __call__
response = self.app(environ, start_response)
File '/usr/lib/ckan/default/src/ckan/ckan/config/middleware/common_middleware.py', line 80 in __call__
return self.app(environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/wsgiapp.py', line 125 in __call__
response = self.dispatch(controller, environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/wsgiapp.py', line 324 in dispatch
return controller(environ, start_response)
File '/usr/lib/ckan/default/src/ckan/ckan/lib/base.py', line 212 in __call__
res = WSGIController.__call__(self, environ, start_response)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/controllers/core.py', line 221 in __call__
response = self._dispatch_call()
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/controllers/core.py', line 172 in _dispatch_call
response = self._inspect_call(func)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/controllers/core.py', line 107 in _inspect_call
result = self._perform_call(func, args)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/pylons/controllers/core.py', line 60 in _perform_call
return func(**args)
File '/usr/lib/ckan/default/src/ckan/ckan/controllers/package.py', line 681 in new_resource
get_action('resource_create')(context, data)
File '/usr/lib/ckan/default/src/ckan/ckan/logic/__init__.py', line 457 in wrapped
result = _action(context, data_dict, **kw)
File '/usr/lib/ckan/default/src/ckan/ckanext-validation/ckanext/validation/logic.py', line 489 in resource_create
resource_id, local_upload=is_local_upload, new_resource=True)
File '/usr/lib/ckan/default/src/ckan/ckanext-validation/ckanext/validation/logic.py', line 624 in _run_sync_validation
u'async': False})
File '/usr/lib/ckan/default/src/ckan/ckan/logic/__init__.py', line 457 in wrapped
result = _action(context, data_dict, **kw)
File '/usr/lib/ckan/default/src/ckan/ckanext-validation/ckanext/validation/logic.py', line 131 in resource_validation_run
run_validation_job(resource)
File '/usr/lib/ckan/default/src/ckan/ckanext-validation/ckanext/validation/jobs.py', line 89 in run_validation_job
report = _validate_table(source, _format=_format, schema=schema, **options)
File '/usr/lib/ckan/default/src/ckan/ckanext-validation/ckanext/validation/jobs.py', line 122 in _validate_table
report = validate(source, format=_format, schema=schema, **options)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/goodtables/validate.py', line 56 in validate
report = inspector.inspect(source, preset=preset, **options)
File '/usr/lib/ckan/default/lib/python2.7/site-packages/goodtables/inspector.py', line 80 in inspect
table_warnings, table_report = task.get()
File '/usr/lib/python2.7/multiprocessing/pool.py', line 567 in get
raise self._value
GoodtablesException: Check "column" is not registered
```

I tried to look at that code try to understand what it's supposed to be registered but I don't get it yet, I'm actually a perl programmer, python is new for me!