[CF-Devel] Changes to the Demonology map

[Peter Mardahl]

Due to a suggestion by philc, I've done the following to the
Demonology maps

1)  The summoners can see invisible.
2)  The undead guardians must be slain in order to ascend the center
tower.
3)  In order to get to the final treasure chamber, the player must
have recently gone up and been marked in all four of the elemental
master towers.

PeterM