ZENGINE: Make the declaration and implementation of copyRectToWorkingWindow be the same
ZENGINE: Make LeverControl render to the working window instead of directly to the screen
ZENGINE: Allow RLF seeking without returning a frame
ZENGINE: Add scr parse line for ActionAssign

It was already implemented, just not added to the scr parsing
ZENGINE: Delete a Control * when removing it from _activeControls
ZENGINE: Set a Puzzle as completed before executing its ResultActions
ZENGINE: Add method for getting a pointer to a Control
squash get control
ZENGINE: Implement AnimationControl

This handles playing animations asyncronously over numerous frames
ZENGINE: Implement ActionPreloadAnimation::execute()
ZENGINE: Implement ActionPlayPreloadAnimation