This enables the second frame of the test video to be decoded.
It appears that the test video uses a superframe (group of multiple
frames) for the first chunk of the file, but we haven't implemented
superframe parsing.
We also ignore the show_frame flag, so for now, this
means that the second frame read out is shown when it should not be. To
fix this, another error type needs to be implemented that is "thrown" to
decoder's client so they know to send another sample buffer.
This changes MotionVector by removing the cpp file and moving all
functions to the header, where they are now declared as constexpr
so that they can be compile-time evaluated in LookupTables.h.
Additionally, this uncovered a couple bugs with existing code,
so those have been fixed. Currently, parsing a whole video does
fail because we are now using a new calculation for frame width,
but it hasn't been fully implemented yet.
This patch brings all of the previous work together and starts to
actually parse and decode frame information. Currently it only parses
the uncompressed header data (section 6.2 of the spec).
