Bump up version number to 0.6.8-DEV
Fix typo: s/.PONY/.PHONY/
Refactor nghttp2_adjust_local_window_size
Do not change user variable CFLAGS in configure.ac
configure.ac: Categorize configure result
configure.ac: Rename some variables so that they follow automake convention
asio-lib: Put ${AM_CPPFLAGS} before ${BOOST_CPPFLAGS}
nghttpx: Fix --backend-http-proxy-uri does not work
nghttpx: Longer downstream HTTP/1 idle connection timeout
building-android-binary.rst: Highlight sh code
doc: Add link to nghttp2.org
nghttpx: Longer read timeouts
nghttpx: Limit # of downstream connections per host when h2 proxy is used

This commit limits the number of concurrent HTTP/1 downstream
connections to same host.  By defualt, it is limited to 8 connections.
--backend-connections-per-frontend option was replaced with
--backend-http1-connections-per-host, which changes the maximum number
of connections per host.  This limitation only kicks in when h2 proxy
is used (-s option).
nghttpx: Don't log access log for blocked streams
nghttpx: Pass NI_NUMERICSERV to getnameinfo to get numeric service name
nghttpx: Support multiple HTTP/1 backend address

For HTTP/1 backend, -b option can be used several times to specify
multiple backend address.  HTTP/2 backend does not support multiple
addresses and only uses first address even if multiple addresses are
specified.
Update doc
Update man pages
Remove altsvc
Support custom memory allocator

nghttp2_mem structure is introduced to hold custom memory allocator
functions and user supplied pointer.  nghttp2_mem object can be passed
to nghttp2_session_client_new3(), nghttp2_session_server_new3(),
nghttp2_hd_deflate_new2() and nghttp2_hd_inflate_new2() to replace
standard malloc(), free(), calloc() and realloc().  nghttp2_mem
structure has user supplied pointer mem_user_data which can be used as
per session/object memory pool.