Modern Beta Forge

• Add ravineChance generator setting, to adjust chance of ravine generation.
• Add min/max value info in tooltip descriptions for ranged (numeric slider or field) settings.
• Improve compatibility with Biomes O' Plenty and Nether API. Classic/customizable Nether settings can now be used while those mods are installed.
• Fix ravines not carving into non-Stone default blocks.
• Fix world customization screen getting laggy when using Classic or Indev chunk sources with very large level sizes.
• Fix GUI bugs.

Technical Changes

• Add STRUCTURE registry and move all vanilla structures here. Structures that are registered here will also be added as a valid target for the modernbetaforge:locate console command.