Added 32 houses, black and red roofs.

Added houses:
4 redroofs & 4 black roofed houses of 6x5,
4 redroofs & 4 black roofed houses of 7x5,
4 redroofs & 4 black roofed houses of 7x6,
4 redroofs & 4 black roofed houses of 8x6

The 2 textures will improve over time, without destroying the 32 models
in this package.
Didn't added the DDS, as it takes more place than the PNG (do not ask
why, I don't know!).
Enjoy, any comment is welcome, as long as it's constructive, to improve
the buildings.