Move definition of END_STREAM flag to DATA and HEADERS frames.
Frame size edits as discussed at the interim
Merge pull request #138 from jasnell/frame-size2

Frame size edits as discussed at the interim
Merge pull request #137 from jpinner/move_end_stream_flag

Move definition of END_STREAM flag to DATA and HEADERS frames.
Merge branch 'master' of https://github.com/http2/http2-spec