glowlights and glowcubes now automatically place floor, ceiling, wall
varieties depending on whether you are pointing at the floor, ceiling,
or a wall.

Removed cross-crafting recipes, took excess lighting nodes out of
creative inventory, added drops for excess models to point them back to
floor or ceiling versions, as appropriate.

This change does not affect old maps or inventories.
Added additional autoplace code for wall lights to turn them into ceiling
lights where appropriate.  Added a number of alternate crafting recipes to
split thick wall lights into thin regular ones or into cubes, and to recycle
excess cubes.