Assorted Lib

4.2.0

• IWorldGenHelper#addCustomSpawner adds a custom spawner to every server level, beside vanilla's own, on both loaders. A factory makes each level its own copy.
• Mods can add creatures now. IPlatformHelper#registerEntityAttributes and #registerSpawnPlacement register a mob's attributes and where it may spawn, and IWorldGenHelper#addSpawnToBiomes adds it to the natural spawns of the biomes. Spawns are added in the same order on both loaders.
• IWorldGenHelper#addSpawnToStructures adds a creature to the natural spawns inside the structures in a tag, wherever one of their pieces is, underground included. It is added to what already spawns there, and nothing is taken away.
• Long item descriptions in tooltips wrap onto several lines instead of running across the screen.