It is illegal to pass an empty audio buffer around.  pcm_resample()
sometimes seems to result in 0 samples, maybe related to
libsamplerate.  To work around that problem, add special checks after
both pcm_convert() invocations.  Removed the pcm_resample()==0 checks
from pcm_convert().

When a response is very long (e.g. a large playlist > 100k songs),
most of it will end up in the deferred buffers.  Filling the deferred
queue is very expensive currently, because a new buffer is allocated
for every client_write() operation.  This may lead to long delays, and
the client might give up and disconnect meanwhile.  This patch makes
MPD attempt to flush the deferred queue as often as possible, to work
around this problem.  Due to the MPD 0.14 code freeze, we should not
optimize the buffering code now.

Move the AC_OUTPUT below the checks. So you nicely see what goes wrong.

Conflicts:

	doc/mpdconf.example

Over time mpdconf has evolved and has been maintained and contributed to by many different folks at different
times. Try to give it some unity. Attempt to clear up some language and make things crystal clear. Add more
examples. Use tabs when it makes sense. Make better borders. Remove obsolete options. Try to put more defaults
when it makes sense.

The "user" option does not work if MPD is started by an unprivileged
user.

Make "secure" a log level different from "default".  "secure" should be
right between "default" and "verbose".  Map "default" to Glib's
"MESSAGE" log level.

If lame was not available, the shout_mp3 plugin was enabled anyway,
and triggered compiler errors.

First check if an ecoder plugin is available, then determine whether
to enable the shout output plugin.

getPlayerErrorStr() assumes that pc.errored_song is set when an error
occured.  Since the song may have been deleted meanwhile, add a NULL
check.

When a (remote) song is deleted from the playlist, there may still be
a reference to it in pc.errored_song.  Clear this reference.

Remove useless computation. After the pthread_cond_wait loop there are at least MIN(od->bufferSize, size) free bytes in the buffer. Thus MIN(od->bufferSize - od->len, size) is always equal to MIN(od->bufferSize, size).

Additionally, add an example in mpdconf.example.

When a client-specified URI has a scheme which is not supported, do
not try to open it as a local file, but provide a meaningful error
message.

uri_has_scheme() checks if an URI contains the sub string "://", which
makes MPD assume that it is a remote URI.

When a file had no file name extension, getSuffix() could return the
extension of the parent directory (if it had one).

The old getSuffix() code was quite wasteful, and can be replaced
completely with strrchr().

Use the C99 "bool" data type instead of "int".

printRemoteUrlHandlers() cannot fail, and does not need a return
value.

The function didn't do anything useful, it was just several lines
obfuscating that it was only forwarding isRemoteUrl()'s return value.

ls.h does not need time.h, do not include it.

When updating from a version before libcurl was used for streaming
support, this is confusing - streaming will work with the old version
(e.g. 0.13.2) but will give "no such file" errors with the new due to
the missing dependency. However, the missing dependency will not be
obvious when running the configure script.

The function strstrSearchTag() used g_utf8_casefold() to generate the
(pseudo-)lowercase version of the song's URL, but it never used the
variable.