Additional asyncio version

[Lukasa]

Rather than port this library to asyncio, why not have a new library that re-uses some common code from here but uses asyncio? That allows easy support of asyncio without limiting the access to HTTP/2.

MORE PROJECTS.

Related: #10.

[Lukasa]

From my previous asyncio experience, I should note that HTTP/2 should be implemented as an asyncio transport. A good example of how to do this can be found here, and should be used as a jumping-off point.

[Lukasa]

Hopefully the changes should be limited to rewriting HTTP20Connection, Stream, and HTTP20Response.

[Lukasa]

This isn't relevant to this module anymore, hyper-h2 owns this kind of thing now.