- differences that work correctly -  (2.92 => 2.91)
* always removes old clip  (no matter what)
removeClip() occurs 0ms before placing the new clip
movieClip linkage waits 0ms before onLoadInit
removeClip()
-	always swaps depths
	always removeMovieClip
	always unloadMovie


- differences that break -  (2.91 => 2.92)
* only removes old clip if it's the same depth
removeClip() occurs immediately before placing the new clip
movieClip linkage waits 1ms before onLoadInit
removeClip()
	never swaps depths
	always removeMovieClip
	never unloadMovie


- what works! -  (2.91 => 2.93)
always remove old clip,  immediately before placing new clip		(this is critical for linkage to work)

- don't need -
- always swaps depths  (can remove)
- always unloadMovie  (can remove)
~ movieClip linkage waits 0ms before onLoadInit  (can be 1ms)
