sprite system can globally cache output frames and share them

_global.CACHE
	sprites
		charsetPath_pose_dir_frame = bitmapData

This allows Flash to internally update multiple movieClips in a natively efficient way.
(perhaps like the conveyor belts?  Does .cacheAsBitmap need to be used, or does this do the same thing?)

RESULT:		No performance improvement  (discard changes)
WHY:			attachBitmap() has to be called every frame to display a different bitmap.  This actually hurts performance slightly.
						this is different from the conveyor-belts which only call attachBitmap() once and simply display the same shared bitmap, which they all modify as needed via copyPixels().


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Possible solution?
If multiple sprites share identical settings...
... and happen to be on the same frame when those settings are applied
... and are currently animating
Then logically they should all be displaying the exact same thing.
Only then should they share the same output bitmap.