new transform system; lots of things are broken
more new transforms (everything is still broken)
more new transforms (still broken)
some cleanup (broken...)
doc
more broken than ever before
fix modifiers on changing original surface (broken)
a little cleanup; performance (broken)
_gen_mods_fill
rewrite modifier undo/apply

still broken: builtin transforms (except fill), GM as a Graphic
some bugfixes
rewrite flip
resize
bugfix
rewrite fill
rotate
make GraphicsManager work as a Graphic again
don't let _orig_dirty grow huge