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.
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
Disable H265/HEVC in codectypes.cpp until it actually gets into
libavcodec.