Add basic tests for scePsmfPlayer and sceMpeg

We don't even slightly pass either of them, and they probably log too much for that to be reasonable.  But at least they're working examples.

Uses the video that was already in this repo, but it'd be nice if we had a few test videos with different properties, haven't tried encoding manually or examining the actual bitstream...

It may not all be right, and I had more code I ripped out where I was investigating the structs themselves.

-[Unknown]