Lots of changes - see extended description

generated textures are right-side-up now,
lights now work correctly between renderings,
updated MaterialUse class and inMaterial,
colored lights look better,
all DrawableDecorators must now implement copyStack(),
copyStack() allows you to create a deep copy of a stack, so you can
spawn things from a prototype,
got rid of annoying build warnings.
made a spawner. Press 's'.

Also, last commit fixed the lights.