OPAL Shaders

OPAL v0.1.1 Changelog:

-Windswept Savanna is now detected as a savanna biome
-Jagged Peaks, Frozen Peaks and Snowy Slopes are now detected as cold biomes
-better cave detection
-decreased sky brightness and sunlight brightness while the player is in a dark area
-decreased night sky brightness and moonlight brightness while the player is in a dark area (minimal difference between bright and dark areas)
-decreased water's sky reflection brightness while the player is in a dark area
-correction to fog color (it's slightly less green now)