~~~~~
* Implement ``tornado_json.gen.coroutine``
* As a fix for `59 <https://github.com/hfaran/Tornado-JSON/issues/59>`_, a custom wrapper for the ``tornado.gen.coroutine`` wrapper has been implemented. This was necessary as we lose the original argspec through it because the wrapper simply has ``(*args, **kwargs)`` as its signature. Here, we annotate the original argspec as an attribute to the wrapper so it can be referenced later by Tornado-JSON when generating routes.