Reuse a single table for content ids to reduce memory use.
Add DEBUG parameter to control printing of mapchunk generation time,
set to false as default.
Add missing noise parameters (parameters are default and unchanged).
Goal: make caves a lot brighter, accentuating glowstone and lava
accents, making walking around without torches possible. The old
light level was barely enough to walk and see edges. This level
feels adequate.
Gimp settings: brightness + 40, contrast + 20.
Large caverns using squashed 3D noise
Less lava, more glowstone, no air pockets
Preserve nether dungeons
Allow light to spread from glowstone and make brighter
Fix 'is ground content' settings, portals should not be
excavated by overgenerated caves
Rack drops itself as normal
Make brick, fence, stair, slab groups consistent
Use 'node sound gravel defaults' for sand
Make brick crafting consistent with default
Make fence recipe output number consistent with default
Make 'emerge area' volume mimimum required size
Add 'find nether target y' function to search for a cavern
floor with space above for nether portal spawn
