zvbi: 0.2.35

Add zvbi library to allow ffmpeg to understand DVB subtitles.

Note the library has some unit tests run with 'make check', two of which
fail on OSX (an issue is open for this on sourceforge), so for now the
Makefile has been patched to skip those two tests.

It's built without-x as the main library doesn't depend on it, only the
ntsc-cc tool which is not useful on OSX.