Remove arbitrary laser limits

For some reason, laser beams. can bounce off a block only if it's colored white. This is a feature that has existed since old versions of Blocksworld. However, a user may want to have other blocks a laser can bounce off of, so this should be turned into an attribute a player can add to any block, like "Phantom" or "Invincible." It may also be helpful if it wouldn't trigger a block that is activated by laser hit.

Another thing is that lasers can pass through a block only if it has the glass texture. This could also be converted to an attribute.