Added texture for the new experimental Build Surface block.

Added 7 new parts: log, spinning block, decoupler, grabber, round metal plate, grip pad and plow.
Updated 2 parts: powered large wheel and unpowered large wheel (improved tyre tread pattern).
Created 3 new color versions: blue edition, military green edition and desert edition (see description).

Added 4 new parts in mechanical category:
- suspension, slider (3D models)
- contractable spring, rope+winch (textures, 3D models not supported)

Added 1 new part: ballast

Added 4 new parts: small wheel, unpowered medium cog, powered medium cog and unpowered large cog