Kh - Flattened out the rotation stuff by moving rotation manipulation
stuff into RotationTableModel
Kh - Fixed double free on program shutdown
Kh - Fix program crash when very quickly deleting multiple singers
Kh - More migration of db tasks to KhDb
Kh - Prevent song play on fast delete clicks (stop double-click play
trigger)
Kh - Move more DB stuff to KhDb
Kh - Table column widths and splitter states now saved and restored on
program start.