test/test_rewind: add missing stdlib.h include

For EXIT_SUCCESS.
PcmExport: add missing <iterator> include

For the range-based loop on a ConstBuffer object.
encoder/shine: require libshine 3.1, adapt to new API

The "written" argument to shine_encode_buffer() and shine_flush() was
changed from "long" to "int", which breaks API and ABI compatibility.
This is a big deal, and it doesn't seem worthwile to keep support for
the (broken) 3.0 release.
Merge branch 'master' of git://git.musicpd.org/master/mpd