HTTP2: Update to draft-16

Also update HTTP Header Compression (to draft-10)

No framing change on HTTP2 draft-16

Change-Id: I7f8ffd7ab37bc22fd6fbe156b0bf52543025e3a8
Reviewed-on: https://code.wireshark.org/review/5782
Reviewed-by: Michael Mann <mmann78@netscape.net>