Import TSV maps generated via donjon

[jghibiki]

Map generator example: http://donjon.bin.sh/pathfinder/dungeon/

The donjon map generator has the option to export maps as a TSV file. We should allow importing these files into a new map. Donjon maps are represented by letters.

• F = floor
• D = door

We just need to surround the floor and door tiles with walls. and place doors where indicated.