Update hologram.lua

Added CPPI to holograms.
Update propcore.lua

A quick fix for propcore.
Fixed up the propcore component and it actually works now.
You can now use propcore to parent props to holograms.
Added not operator for Entity class (!Entity).
Right clicking gates with tools now shows you the code.
Overlay now shows you the Ops as well as percentage.
Added E:getMaterial() and E:setMaterial(S).
Merge branch 'master' into dev