start-range and finish-range should graphically show the range being created.  also add bindings for comma and period  in addition to existing bindings which require a numpad.  the old ones are now alternates.  all primary functionality should appear on the qwerrty, and the numpad should be considered  an ergonomic redundant alternative if you have one
add a method to cancel a pending play_range.  this is needed when we are modifying the range with keyboard commands.