[mythtv] mtd: libdvdread vs libdvdnav

[Anduin Withers]

> I'm currently looking into converting Myth Transcoding Daemon to use 
> libdvdnav (as libmythdvdnav) instead of libdvdread because this is what is

> used when actually watching DVDs in the first place (removes a dependency)

It removes exactly zero dependencies; dvdnav contains dvdread, mtd has been
using libmythdvdnav for some time.

> Any other general guidence will be welcomed also!

You should just fix the vobu cell traversal code, some next step sanity
checks should make things better.

-- 
Anduin Withers