Don't place the player in the centre of Zig floors

In theory this seems like a good way to make later Zigs more lethal, but in
practice placing the player in the centre of Zigs just makes the already
predominant methods of clearing Zigs better or just as good (Tornado/Shatter
with Makhleb, etc) while making other techniques even weaker than before, as
well as reducing the distance from the entry point to the stairs.

This reverts commit 77f51cb4a003ccbc8d186bd7b91638c35c47efcc.
Remove/adjust some ghost speech lines
Reduce the MP cost of wand MP mutation
Revert more of Christmas

This reverts commit 902f3e98ec3af1bc6ddebc8bdbf844603c7f45bd.