Added a few images.
WIP
Added new graphic files that MAY be used in the final game.
Added building classes.
Building class.
Building a house (WIP).
Building drawing (WIP).
Building front wall (wip).
Building a city (WIP).
Building house (wip).
Building houses (wip).
Build a simple house.
Merge branch 'feat005-cities' (closes #5).