Apologies for the enormous commit, but I don't see a way to split this
up nicely. In the vast majority of cases it's a simple change. A few
extra places can use TRY instead of manual error checking though. :^)
This patch brings all of LibVideo up to the east-const style in the
project. Additionally, it applies a few fixes from the reviews in #8170
that referred to older LibVideo code.
This commit initializes the LibVideo library and implements parsing
basic Matroska container files. Currently, it will only parse audio
and video tracks.
