Add/discuss the possibility for near/far texture option in terrain-shader

[MathiasBaumgartinger]

Especially for trees/shrubs the foliage texture can result in weird color. While the texture looks perfect for being inside of a forrest, (i.e. brown foliage on the ground), the mix-function on the detail_color and ortho_color looks far to brown for woods in the distance.

Optionally, we could just make the texture greener (example below).

[MathiasBaumgartinger]

Also this prevents the hard "cut" from rendered individual trees to ortho image.