- On "stop": if "playing" cancel autoswitch; break "playing".
- On "start show": set up things; set "playing" state; show needed image.
- On "stop show": cancel any schedules, hide things.
+ - On resize: recalculate existing image size and position; determine
+ what image is needed; if it is not the one on display then request
+ "show image" for the new image.
*/
var Show = new Class({