basics for hologram projector
Merge branch 'master' of https://github.com/MightyPirates/OpenComputers into holo
textures for hologram projector block; caching display list for hologram; fixed item bounds; added localization; added clear and fill callbacks; fixed pcall and xpcall being exploitable to avoid timeout enforcement
added power consumption for hologram projector; added scale setting, so hologram can be from 1x1x1 up to 9x6x9, higher scale consumes more energy
fixed possibility of math.random pushing a LuaError (userdata); fixed shell immediately restarting after errors if there were pending signals