* The crumbly floor doodad was made 50% larger.
* New doodad: Small Key and Small Key Door. These work like the colored
doors and locks except each Small Key is consumed when it unlocks a
door. The door's appearance is of iron bars.
* The inventory HUD displays a small quantity label in the lower-right
corner of items that have a quantity, such as the Small Key. This is
done as a Canvas.CornerLabel string attribute on uix.Canvas.
* The "give all keys" cheat adds 99 Small Keys to your inventory.
* The colored locked doors and the Electric Door are increased in size
to better match Boy's sprite size.
* Colored doors now have a "locked" and "unlocked" state when closed;
when locked, a gold padlock hangs on the door with a keyhole shaped to
match the corresponding Colored Key.
* Revamped the sprites for the four colored locked doors. They now have
a side-view profile perspective rather than a front view.
* Doors open facing the left or the right based on what direction the
colliding actor approached it from.
