Move CONTRIBUTING.ms and LICENSE.txt back to root of repository.
Second attempt at fixing infinite loop when mapgen can't find anywhere to put a staircase.
Nuke some accidentally merged debug messages.
UIMenu: Start scrolling in the middle of the list and keep the selection centered as long as the list isnt at the top or bottom.
Interface option for centered menu scrolling.

So far supported by uimenu.
Merge scrolling changes.

Conflicts:
	options.cpp
	ui.cpp
Default to center-scroll.
Don't cache center scroll setting so you can toggle it in-game.
Merge some small bugfixes