Rewrite tornado_utils for >3.0

This makes use of coroutines and the new Futures interface.
Also, no more monkey patching. Integration BlueOx into a tornado
app is not much more straightforward.
Leave logging configs in Django to normal LOGGING settings
Fix issue with custom tornado coroutine implementation.

Previously, we were not properly returning the value. Wrapping and
proxying a generator is delicate business. Test case is also
enhanced to make sure that is the case.
oxstash