Play track
	cause
		menu command (play or skip to next)
		autoplay
		back to last track
	track assignments (modify for "back to last track")
		last = current
		current = next
		next = None
	other
		update last / current / next track display
		timers to new current
		show track as played
		update start time for remaining tracks
		record track as played
		if playing, fade current over 1 second
During playback
	Update timers
	Update time colours
	Status bar Total remaining playlist time
	Stop
	Fade
Playlist management
	Save playlist
	Load playlist
	Add track to database and playlist
	Reorder playlist
	Remove track
	Add track
	Clear playlist
	Track properties
	Copy track
	Paste track
	Clear selection
	Track volume analysis
	Open track in Audacity
Display
	Remember window size
	Remember dialog size
	Remember playlist column sizes
	Top: previous, current, next track
Misc
	Logging
	Preferences