Vim control lines were re-introduced or not entirely cleaned up.
This nukes them again.
Removing from embedding, extensions, gfx, hal, ipc, layout, mailnews,
media and memory. More to come.
Structure of code was slightly modified so that it should be no longer necessary to re-generate the config_*.h files, greatly simplifying the resync process in the future.
FFmpeg requires specific default values in AVCodecContext to be set. Instead of manually setting these each time we resync with upstream, let's use FFmpeg's own AVOptions which automatically sets all the values to their default.