Humidity-related Desert variants.

Current Deserts has no humidity variants. So they can unrealistically generate near Jungles or Mangrove Swamps. I suggest two extra variants of Deserts.

• Dryland. A extremely dry version of Desert. Uses White Sand (please add it and related blocks) instead of Sand, highlighting the theme of bore and death. No plant spawns there. Lava generates frequently. Killer Bunnies can naturally spawn. 
• Oasis. A wet version of Desert. Uses Red Sand instead of Sand. Cactuses generate more frequently and are much taller. Lakes and Grass Blocks can also spawn.