Upgraded Cactus and Windmill textures

The cactus textures have been upgraded with better bump map extrusions (courtesy of pictures of actual cacti) and a pattern resembling actual plant cellulation, and the windmills have rust and metal corrosion.  Here's some pictures showing that.

Yeah, the cactus side is still being difficult.  I think the geometry is to blame here.

I know that the ground doesn't have a texture on it; that's being worked on a different file and being put into to this one.