Portalmod: Glacier

- added gravity changing cube that has the same gravity as a normal cube but changes directions based on the surface it touches
- added hopping cube, jumps around randomly when the player isnt looking
- added death fizzler and laser field
- added old apperature versions of all existing cubes besides the varied scale cubes
- made space cubes get a bit of downforce to come out of cube droppers properly
- fixed sensor texture being middle when placed vertically
- made space cube have no air resistance so it flies forever
- added bunny cube which is identical to the hopping cube but it follows the player when holding a carrot
- added a config that makes it so you can choose between combined creative menu and not combined creative menu