You can now destroy labels, buttons, and images.
Created a common implementation of destroy() for all controls.
Control tables are now cleared out when a control is destroyed.
You can now also destroy text boxes.
Events registered with common.add_event() are now unregistered when you destroy a control.
Mouse event handlers are now unregistered when you destroy a control.
Fixed a crash where a destroyed control still responded to resize events because of anchoring.
Updated the documentation.
Renamed common.make_control() to common.is_destroyable().