Native http2 stack

[dpwspoon]

This library is intended to provide a consistent caching behavior for http2 implementations AND to provide notifications when push promises are sent/delivered. We have currently implemented the lowest common denominator, which is assuming the browser supports websocket. We then provide an http2 stack over websocket AND a consistent caching behavior for requests/responses AND push promises.

Most browsers now support http2 but vary greatly in their caching behavior for http2 push promises. Ideally, for these browsers this library would use native http2 stack WITH special support for emulated http2 push promises/caching behavior. Design for how to best do this is required (perhaps deliver push promises on a Server Sent Event stream).