[crossfire] block view vs. xray vision

[Mark Wedel]

  Note also that high level electric dragons get x-ray vision as a free bonus. 
So you end up with potentially a lot of characters having that ability.

  As far as color of objects through walls - that isn't something that can 
really be controlled - the client makes non visible stuff grey on its own (for 
fog of war).

  There is not currently anyway for the server to tell a client that a space 
should be drawn in grey.