Updated ProRes to allow transparent output when set to Profile 4. As
part of this change, pix_fmt is no longer explicitly set for ProRes, but
the expected format is automatically applied from for each profile.
Added rgba as an output pix_fmt for the nvenc formats. These have not
been tested and may not function.
Fix incorrect escape in Advanced Preview code.
Audio settings are now stored in video_formats
Updated video_formats with reasonable defaults for audio
A Load Audio (Path) node has been added
Audio Loads are cached with load state and only occur once.