fixed bugs with showing correct game buttons for various cases

fixed bugs with showing correct game buttons for various cases

This change should fix problems (like multiple mapped or wrong buttons
at the same screen position) with various combinations of game button
positions (if defined in custom artwork set) and setup options to show
load/save buttons and/or undo/redo buttons (which might happen because
stop/save/undo buttons and play/load/redo/restart buttons are defined
to be at the same screen position by default).