`track-list` is now filtered by the currently selected edition
add `edition-list/N/metadata` sub-property
add `program_id` support to EDL `!track_meta` header
add `--flatten-editions` option to disable program-based edition grouping
add `track-list/N/program-ids` sub-property
deprecate `track-list/N/program-id` in favor of `track-list/N/program-ids`