Implemented teleportation crystals.

Transportation to and from Nyx is now possible. Nyx is quite desolate
and has no real features at the moment. But it's possible!
Added/modified some files necessary for teleportation to work.
Added textures and localized names for teleportation crystals.
Made the teleport crystal be used for 72000 ticks if inactive.

Effectively fixes a bug in which the shadow creeps in even if the
crystal is inactive.
Added animation to the teleport crystal.