cleanup: remove unused function in TileImages
TileImage: promote SwitchImage to top-level class
MakeTiles: an alternate method of enumerating frames
MakeTiles: refactor some code into new drawFrames() function
TileImage: move Animation class from MakeTools into Graphics package
TileImage: eliminate redundant Animation class
TileImage: allow Animation to be a fragment of larger xml file
Animation format: convert to more xml-ish format

and make it consistent with the format used by tiles.idx
cleanup: remove realizeAll() implementations

since I decided this wasn't the best way to meet the need
(and it was overly complicated)
TileImage: remove support for making animation with <switch> image
MakeTiles: expand each frame of an animation
TileImage: got animations working again
cleanup: remove no-longer-used realize() method from TileImages