configure.ac: prepare for 0.18.14
test/test_protocol: unit test for protocol/ArgParser.cxx
protocol/ArgParser: fix integer overflow in parse_range()

Casting std::numeric_limits<unsigned>::max() to "long" leads to an
overflow if sizeof(unsigned)==sizeof(long), and the result will be -1.

This happens on some 32 bit architectures, for example ARM and WIN32.

Workaround: use std::numeric_limits<int>::max(), which is the largest
signed integer.  Since sizeof(long)>=sizeof(int), this will never
overflow.

Fixes Mantis ticket 0004080.
decoder/audiofile: fix crash after seeking

Log call was added to the wrong branch.

Fixes regression by commit ca1a1149
DecoderThread: clear the pipe when handling late SEEK

See code comment.  Fixes assertion failure in
decoder_command_finished().
Decoder*: add more assertions
decoder/ffmpeg: pass MIME type to ffmpeg/libav version 11

That attribute was uninitialized before, which could crash
libavformat.

See Debian bug 760669
decoder/ffmpeg: use memset() to initialize AVProbeData
test/run_decoder: dump MixRamp data
release v0.18.14
Merge tag 'v0.18.14'