Biome Generation
The current biome generation algorithm is weird, this makes it difficult/impossible to adapt to the new 'feature' system. Other features depend on the biome for the current slice, which depends on biome markers for uninitialised slices. We need a better system which gives each slice a biome type, which can be calculated for each slice independently, but still have a low frequency across many slices.
We could just give each chunk a biome type, but that would be a bit boring.
The current system is very broken.
Do it the same as the new hills
Not particularly relevant because it uses attributes of the regions to picl the biome: http://www-cs-students.stanford.edu/~amitp/game-programming/polygon-map-generation/#biomes
Although the way it generates the regions could be useful... https://en.wikipedia.org/wiki/Voronoi_diagram
We could go back to the random biome per chunk, but randomise the boundary of the biome within the chunk.