Valleys Mapgen 2.1

There are now 4 trees : the pseudo-pine tree from 2.0 has became real fir tree with its own textures (from Forest), and I've re-added pine tree with a different shape :

There will be more trees from Forest in the future.

Dry shrub and cactuses have been reworked : they are a little more common.

Rivers have changed : their floor has been made smooth instead of the old square profile. Now I use the River Water Source to generate them (it can be changed in settings).

Some screenshots :

Average mapgen time : 600 ms on my computer.