mpd version 0.16.3
Modify version string to post-release version 0.16.4~git
fd_util: add function socketpair_cloexec_nonblock()
doc/user: Typo in playlist plugin documentation, 'playlist plugin' not 'filter'.

This patch fixes a typo in doc/user about playlist plugins.

Its in the top commit in my repository in a branch called 'doc_fix':
git://github.com/mcfiredrill/mpd.git
ffmpeg: workaround for semantic API change in recent ffmpeg versions
decoder/flac: validate the sample rate when scanning the tag

Don't calculate the song duration when the sample rate is 0 (division
by zero crash).
doc/protocol: add some missing specifications
decoder/ffmpeg: use AVIO_FLAG_READ on newer ffmpeg versions

FFmpeg/libav have dropped AVIO_RDONLY in favor of AVIO_FLAG_READ. This
patch fixes that in MPD.
test/read_conf: fix -Wunused-but-set-variable
test/read_conf: make variables more local
test/run_filter: remove unused variable "frame_size"
configure: correct avahi/bonjour state on result page

Was always displayed as "no", even if one was found.
ape: add missing g_free in error path
sticker: fix a memory leak
conf: add missing fclose in error path

This patch seems a bit ugly, maybe it would be a bit cleaner with gotos.
output/ao: add missing g_free in error path
output/httpd: add missing g_free in error path
output/recorder: fix a memory leak
output/shout: fix a memory leak
NEWS: fix memory leaks