Spray of (minor) vault edits

Mostly little syntax errors and clean-up, mild blockings of undesirable
behaviours like dangerous monsters teleporting / digging out from glass,
fix-ups after feature deaths, and so on.

Particular highlights:
 * Majin-bo is now in the Hellbinder's (reliably) and Crypt:$ (sometimes).
 * lemuel_statue_in_the_mist, a vault which fundamentally contradicts itself,
   has had the monster-statue placement moved over to a new Abyss placement,
   where it can actually work to put obscuring clouds over a statue.
 * The kobold artificer in blue_anna_alchemist is now a big kobold artificer,
   not that it's any dangerous still.
 * Trim out some statues and one bland vault from the de-gimmick-ified set of
   dk_noncrumbling, it's a tiles eyesore and a bad precedent of excess terrain
   use.
 * Grunt's generic ministair and megastair vaults no longer place trees in
   Crypt, Zot, or the Hells. Previous position applies alongside it being
   absurd to see trees in the Hells in the first place.
 * lemuel_elevator is more rare outside of D, and in such placement also has
   an ambushing monster present and adjacent to make people's day with the
   otherwise generous stair arrangements.