decoder/ffmpeg: use avcodec_descriptor_get() to determine codec name

In version 11, both ffmpeg and libav deprecate
AVCodecContext::codec_name.  The function avcodec_descriptor_get() has
been introduced long ago.
util: Fix header for strcasecmp

According to POSIX and both OSX and Linux manpages,
strcasecmp comes from strings.h, not string.h.

Most OSes also have them available in string.h,
but we just fixed the headers on Haiku and it now
only provides them in strings.h.

We might want to fall back to string.h for other
OSes though...

cf.
http://pubs.opengroup.org/onlinepubs/009695399/functions/strcasecmp.html
http://linux.die.net/man/3/strcasecmp
https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/strcasecmp.3.html
icu: include strings.h for strcasecmp

Again, POSIX says strcasecmp is not in string.h.
pcm/SoxrResampler: add missing string.h include
Merge branch 'v0.18.x'
PlayerThread: rename player_create() to StartPlayerThread()
decoder/dsf: fix indent
Report bitrate for DSF and DSDIFF DSD decoders
decoder/dsf: Allow up to DSD512. Enable DSD rates based on Fs=48kHz
input/ffmpeg: use "auto"
input/ffmpeg: refactor error code path
input/ffmpeg: update offset after seeking
{input,decoder}/ffmpeg: move ffmpeg_domain to lib/ffmpeg/Domain.cxx

Eliminate duplicate definition (in input plugin and decoder plugin).
input/ffmpeg: use av_strerror()

Generate more detailed error messages.
decoder/audiofile: check InputStream::KnownSize()

The plugin assumes that the size is known, but does not verify it at
runtime.
InputStream: use KnownSize() in assertion
decoder/dsf: remove unnecessary ID3 offset check

If the offset is out of range, the seek will simply fail.  Not a
problem.
decoder/dsf: check InputStream::KnownSize()
decoder/DsdLib: check InputStream::KnownSize()
decoder/DsdLib: use fixed-length ID3 buffer

Variable-length arrays are not allowed in C++.