Allow loose/strict URI checking levels also for decorators and component API

Capital letters are not allowed in registered URIs. For example, @register('example.camelCaseFails') fails:

#!/usr/bin/env python3.6
# -*- coding: utf-8 -*-

from autobahn.wamp import register
from autobahn.twisted.wamp import ApplicationRunner, ApplicationSession

class Example(ApplicationSession):
    @register('example.snake_case_succeeds')
    def foo(self):
        pass

    @register('example.camelCaseFails')
    def blah(self):
        pass

ApplicationRunner(None, None).run(WampServices)

Raises

Traceback (most recent call last):
  File "./autobahn-register-camel-case.py", line 7, in <module>
    class Example(ApplicationSession):
  File "./autobahn-register-camel-case.py", line 12, in Example
    @register('warden.camelCaseFails')
  File "/usr/local/lib/python3.6/dist-packages/autobahn/wamp/uri.py", line 343, in decorate
    f._wampuris.append(Pattern(real_uri, Pattern.URI_TARGET_ENDPOINT, options))
  File "/usr/local/lib/python3.6/dist-packages/autobahn/wamp/uri.py", line 215, in __init__
    raise Exception("invalid URI")
Exception: invalid URI

Googling, the only related discussion I found was

https://groups.google.com/forum/#!topic/autobahnws/mkjF21Fb8ow

Why, by default, are capital letters (e.g. for camelCase) not allowed in registered URIs?

Start in autobahn/wamp/uri.py at the register decorator and Pattern validation, then trace how ApplicationRunner and ApplicationSession expose component registration. Determine how loose and strict URI checking levels should be passed through decorators and the component API, and verify that the default behavior remains defined and covered by the relevant tests.