examples: Guard include config.h with HAVE_CONFIG_H
Fix last warning found by Clang Analyzer

nghttp2_session.c:636:3: warning: Branch condition evaluates to a garbage value
Merge branch 'scan-build' of https://github.com/alagoutte/nghttp2 into alagoutte-scan-build
Merge branch 'alagoutte-scan-build'
nghttpx: Store PID to Config again after daemon()
libevent-server: Enable ECDHE ciphers
libevent-server: Disable SSLv3
nghttpx: Use cached get_config()->pid in save_pid()
Add contribution guidelines
Add .clang-format config file and git-clang-format from clang project
Add pre-commit script
Add make clang-format
Reformat lines with clang-format-3.5
Merge branch 'clang-format'
nghttpx: Submit RST_STREAM if HEADERS appears in the middle of a stream
Just ignore HEADERS with non-idle stream ID and not found in stream map
Issue connection error if client receives HEADERS with idle stream ID

If stream ID is not idle, it might be valid HEADERS.  If stream ID is
idle, it is invalid regardless stream ID is even or odd, since client
is not expected to recieve request from server.  nghttp2 library
historically allows this, but now we forbids this.
Cleanup previous commit
doc: Add language attribute in asio_http2.h.rst.in
Robust GOAWAY handling

This change will utilize last_stream_id in GOAWAY extensively.  When
GOAWAY is received with a last_stream_id, library closes all outgoing
streams whose stream_id > received last_stream_id.
nghttp2_on_stream_callback is called for each stream to be closed.

When GOAWAY is sent with a last_stream_id, library closes all incoming
streams whose stream_id > sent last_stream_id.
nghttp2_on_stream_callback is called for each stream to be closed.