ProcessExecutor failing

(using osx, python 3.5)

seems to be trouble with using promises and pickle together. Also decorated methods seem to have trouble which means resolvers are often a problem. Adding a comma to args fixes the "Queue is not iterable" error but the second error is much more intricate.

```
ERROR|2016-10-01 01:12:57,673|graphql.execution.executor >> An error occurred while resolving field Query.viewer
Traceback (most recent call last):
File "/Users/ben/.virtualenvs/current/lib/python3.5/site-packages/graphql/execution/executor.py", line 190, in resolve_or_error
return executor.execute(resolve_fn, source, args, context, info)
File "/Users/ben/.virtualenvs/current/lib/python3.5/site-packages/graphql/execution/executors/process.py", line 29, in execute
_process = Process(target=queue_process, args=(self.q))
File "/usr/local/Cellar/python3/3.5.2_1/Frameworks/Python.framework/Versions/3.5/lib/python3.5/multiprocessing/process.py", line 80, in __init__
self._args = tuple(args)
TypeError: 'Queue' object is not iterable
[01/Oct/2016 01:12:57] "POST /graphql? HTTP/1.1" 200 116
Traceback (most recent call last):
File "/usr/local/Cellar/python3/3.5.2_1/Frameworks/Python.framework/Versions/3.5/lib/python3.5/multiprocessing/queues.py", line 241, in _feed
obj = ForkingPickler.dumps(obj)
File "/usr/local/Cellar/python3/3.5.2_1/Frameworks/Python.framework/Versions/3.5/lib/python3.5/multiprocessing/reduction.py", line 51, in dumps
cls(buf, protocol).dump(obj)
TypeError: can't pickle _thread.lock objects
```

Bắt đầu với graphql/execution/executors/process.py và đường dẫn gọi trong graphql/execution/executor.py, sau đó tái hiện báo cáo trên macOS bằng Python 3.5. Điều tra cách xử lý đối số Queue và lỗi pickling liên quan đến các resolver được trang trí và promises. Được xem là hoàn tất khi các lỗi Queue và _thread.lock đã được báo cáo không còn xảy ra trong quá trình thực thi resolver.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.