last #U1233 - doppelganger shapes (trunk only)

last #U1233 - doppelganger shapes (trunk only)

     My last fix from the Dec'04 report sent by <email deleted>.  Many of its remaining observations/complaints are
about things which aren't bugs.  This implements the suggestion that
doppelgangers should take on humanoid form, although it doesn't take away
the 1/7 chance for pick_nasty() and it can still fall back to arbitrary
shapes when it doesn't pick a humanoid within 5 tries.  This also allows
doppelgangers to take on the shape of the various quest guardian monsters
[mostly the quest leaders' attendants, although there is at least one
extra foe (ninja)].  It excludes the quest guardian for the player's own
role, and I don't think there are any cases where it can yield unexpected
quest guardian behavior.

     This also allows specifying monster class (via description or letter)
when #monpolycontrol asks for type of monster to give to a polymorphing/
shapechanging monster.