Refactor deeply nested if blocks
nghttp2_session_on_window_update_received: Split into 2 functions
Add doc about returning 0 from recv_callback
nghttpx: Fix CONNECT fail on SPDY upstream
Increase NGHTTP2_HD_MAX_ENTRY_SIZE to 3072
nghttp: Code cleanup
Make hd encoder ordering aware and one-pass

The encoder algorithm is simplified and it now preserves ordering
of the headers. It also becomes one-pass encoder.
Fix resource leak
nghttp: Initialize flag to 0
nghttpx: Fix resource leak
src: Use std::unique_ptr for nv
Update doc
Remove unused functions/macros
Fix cosmetic errors
Merge github.com:tatsuhiro-t/nghttp2