Update to 29.1 based on PR 225652 which updates to 29.0
Convert multimedia/mythtv-frontend into a slave port of multimedia/mythtv
They were 95% the same port and it didn't make sense to keep two full ports
of mythtv. This will make future updates less complicated since patching
only needs to be done in one place now.
Known security vulnerabilities in FFmpeg have been addressed.
VuXML needs to be updated to unmark the new version as vulnerable.
CDIO support has been fixed in audio/mythplugin-mythmusic. It looks like this
has been broken for a long time, so I guess nobody uses it.