added bounds check for corner case on button release; fixed typo in method name
added bounds check for corner case on button release; fixed typo in method name

walterbender/turtleconfusion,walterbender/turtle3D,walterbender/turtleart,walterbender/turtleartmini,walterbender/turtleflags,AlanJAS/turtleart,walterbender/AmazonasTortuga