Bump shared library version

Should have been done for 2.18 since it dropped the postproc-related
functions, but oh well.
Replace INCLUDES with AM_CPPFLAGS to please automake
Remove FFMS_SetOutputFormatV

It's been deprecated for two years and the soname is changing anyway so
it's a good time to finally remove it.
Merge branch 'master' into cplugin_master

Conflicts:
	Makefile.am
	Makefile.in
	aclocal.m4
	configure
	configure.ac
	depcomp
	missing
Synchronize src/avxsynth with AvxSynth + 2.18
Revert "Fix shared builds with MinGW"

This reverts commit 7e11704ab32daffcd10c8e7f276d9e1ec147027e.

If --enable-avisynth is used, this causes ffms.cpp to fail
compilation.
Bump version.
Add detection of Opus to Matroska IDs in codectype.cpp
Fix alignment of the Matroska IDs after adding A_OPUS/EXPERIMENTAL
Add H265/HEVC to the Matroska IDs in codectype.cpp

The V_MPEGH/ISO/HEVC designation is part of the draft for HEVC's
inclusion in Matroska.
Merge pull request #124 from qyot27/new_codectypes

Add Opus and (tentative) HEVC to codectypes
Fix compilation with things other than ffmpeg master. Closes #126.
Merge branch 'master' into cplugin_master
Symlink libffms2.so into $libdir/vapoursynth when installing.

With the new plugin autoloading feature in VapourSynth, this
relieves the user of having to manually copy or symlink FFMS2
into the autoloading directory themselves.

The symlinking only occurs on non-Windows OSes, since on Windows
there isn't any significance to the placement of ffms2.dll anyway
(and because true *nix-style symlinks on Windows are a dark art).
Enable user to set VapourSynth and AvxSynth plugin directories
Merge pull request #125 from qyot27/cplugin_master

Minor HEAD catchup + fixes