create 3d assets for trees and bushes

[methusalah]

We need a lot of assets to add to the terrain : bushes, trees of all type, from realistics to alien, and giant mushrooms, big flowers, ferns.

These models will need skeletons to create a wind effect. Why not animations.

[roroah]

Duplicate of #44 !?

[methusalah]

Indeed.

#44 asked for exemple sets, to test the code. I close it and i will reopen individual issue for each need.