Forgot a lot of libffms->libffms2 renaming in GNUmakefile.

Mostly affected the static library.
Update the pkgconfig file generated by configure.

This brings it into line with the one generated by autotools on
the master branch.
Support HEVC decoding when using libav
Fix compilation with libav
Merge pull request #138 from qyot27/libav_hevc

libav: compilation fix + HEVC decoding
Fix use of deprecated frame allocation API

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
Merge pull request #139 from dwbuiten/elenrilsux

Fix use of deprecated frame allocation API
Relicense VapourSynth.h to MIT with permission from author

Closes #140.
Merge branch 'master' into cplugin_master
Merge pull request #141 from qyot27/cplugin_master

HEAD catchup + better install/pkgconfig parity with master