Lighting-related block variables

[LO1ZB]

Not definite as I don't do client side stuff but it seems likely. Note that we don't transmit our lighting calcs, its only used for server side stuff like mob-spawning.

That can cause problems when a player lighten up his house, he thinks that the light level is high enough, to prevent mobs from spawning, but it isn't on server side.
The result from the calculation has to be 100% the same on client an server side.