Adding rooms.clj, needs code to add doors and traps.
BROKEN
Now showing traps!
Got a door, put a trap, hell yeah...
Traps now spawn in walls of the rooms.
Implemented doors, curr no way to close.
Traps now look like lighter walls (temp)

- Refactored some door code, e.g. door-take-damage-fn.
- Open doors are now properly under most things.
Added temple-wall & indestructible walls.
Minor refactorings.
Arrow-traps now shoot in the room!
Now adding (w*h)/2 num of rooms to the desert.

Also added a 1 block thick padding to the outside of rooms.
Temple-walls are now a <wall> & therefore block sight.
add merchant to rendering
add a basic merchant entity with merchant level
player starts on level 1
Arrow traps now take a turn to reload, and notify the player about a "ticking sound".
Moved traps.clj to arrow-trap.clj.
Now adds an arrow trap per wall, ie always 4 per room.

- Major refactoring of room->points code, might want to move letfn’s to
a defn.
enable travel to merchant level and back
remove merchant portal from level once player enters