Roofstuff

Added an option to add details to the roofs. A list of custom objects  is used to randomly 

scatter stuff, here it is used on all the flat roofs. Same goes for details to the street level. Trees, cars,

lightpoles etc are scattered around each block. The streetstuff can be added as proxies, as they tend to

increase the polycount by...^2 or so.

Stuff on the roofs

...and in the streets