Upgrading to HTTP/2 draft 14 HTTP/1.x message flow

Motivation:

HTTP/2 draft 14 came out a couple of weeks ago and we need to keep up
with the spec.

Modifications:

-Allow informational type messages to be sent up the pipeline immediatley.
-Corrections to HttpObject comparitors to support test cases
-New test cases to support sending headers immediatley
-Bug fixes cleaned up to ensure the message flow is terminated properly

Result:
Netty HTTP/2 to HTTP/1.x translation layer will support the HTTP/2 draft message flow.
Would it make sense to resolve the priority discussion as part of issues https://github.com/netty/netty/issues/2804 or https://github.com/netty/netty/issues/2794?  That way we can finish this PR and either fix/remove/resolve the priority related stuff in a follow up PR?