Last few days I working on fixing some issues in the procedural landscape shaders, and added some new features.

First, canyons and rivers were back! They was "flooded" by volcano lava and does not appear in 0.972. Also, I made better mountain range function, and use it for canyons as well (probably saving few hundred instructions).

Canyons:

New mountain ranges

Mountain and canyon walls with steep slopes now have sedimentary layers texture, like in SE 0.84:

Added some variety for volcano shapes, now some of them are conical, more resembling Earth volcanoes:

New sand dunes function, windward and leeward sides have different slopes (although it may be not visible on screenshots):

Other updates:

- Fixed the physical VRAM size detection on ATI
- Fixed a bug with the only one planetary nebula model being used per galaxy
- Fixed nebula model cut in the impostor rendering
- Fixed a bug with stars scale did not applied at program start
- Fixed changing of the lens flare color in the "norm" mode
- Fixed disappearing of a star-like particle of dim brown dwarves illuminated with a main star
- Fixed disappearing of a star-like particle of hot asteroids and dwarf moons
- Bigger ClipZNear to reduce z-fighting
- New video memory limiting system