Ghosts can't use the Move-Upwards and Move-Down verbs

[Cartlord]

Testmerges:

#362
#367
#370
#375
#380

Reproduction:

Observe. Move-Upwards, get the "You are not Superman." error. Move-Down. Get put in a black void , even if you were on Z3 and trying to move to Z2 (surface).
will be closed by #383

[JustLoveBeingAnOwl]

If I recall correctly it was removed entirely since if you attempted them you'd go into a void and suffocate or something.

#383

Just got posted this minute so go check it out.

[Aurrain]

Fixed via PR #383