circular rooms

- minor modifications to add circular rooms, and a room with columns
- since columns were creating doors everywhere, I remade the place_doors
so that it is only run for each room, instead of every cell in the whole
map, so I can also disable it for "special" flagged rooms

- REMEMBER that member functions that are passed an object need the &,
or they only have copies of said object:
void create_column_room(Rect &inroom){