This feeds into efforts to create a working install target.
The order of headers is still funky, and was "fixed" by clang-format,
but in a way that doesn't exactly align with the style guide. Further
cleanup of header order is coming in a follow-up PR.
- Implemented according to v1.0 spec @ https://www.webmproject.org/vp9/mp4/
- v0 is no longer supported
Change-Id: I189c813d788400beda797eea7da943a83dfa7d79