Mysterious BaseCitizen character spawning inside houses

[AndyTechGuy]

When testing #47, a mysterious error message would fill up the console after a little bit of time in the game inside a city:
[main] ERROR o.t.m.minimap.CharacterOverlay - No icon found for citizenMetalRenegades:baseCitizen

An icon for the baseCitizen type of character doesn't exist in the overlay system, so an error is thrown every time the minimap has to display this type of overlay. These error messages are not the fault of the overlay system, but rather point to the existance of an untracked BaseCitizen character inside the world. I added an additional icon for this type of character (blue gooey), and these characters showed up in the middle of some residential houses:

If I looked in just the right spot, I could also see the tooltip of the character. This tooltip had a blank icon and no name:

These characters likely come from an error in the CitizenSpawnSystem, and could be a major memory leak in the game if left unchecked.

[AndyTechGuy]

Fixed by #36.