Adds a new world type which generates configurable biomes with set radius at overworld origin. Default configuration generates a small island with a lava lake and nether-like wasteland surrounding it. Outside the configured biome radii, overworld generates normally, making this world type an odd mix of skyblock/escape the island and regular survival.
For server hosts:
To enable on server, set level-type to "hcisland" in server.properties (and paste custom generator settings to generator-settings)
