Cascades (Hybrid Beta)

Fixes:

• Reduce proportion of flooded caves
• Stop some of the leaves of fancy oak trees in Seasonal Forests from decaying upon generation
• Add terrain beard to Plains villages

Changes:

• Reduce amount of tall grass in Plains, Meadow, and Savanna
• Reduce foliage density in Jungles
• Make fancy oak trees in Seasonal Forests crazier
• Change surface rules to reveal stone in areas where dirt layer is one block deep