Feature suggestion: Allow 1:256 Biome Layer to count instances of biomes

[Delvin4519]

As is above: allow 1:256 Biome Layer to count instances of biomes similar to how Temperature Categories allow one to count instances of certain temperatures. EDIT: Related with #63 and #173 .

Example use case: One can find a larger swamp by checking a 3x3 area around 0,0 (centered square = 2) for 9 tiles of Swampland.

Right now, one must exclude every single other biome to reproduce the above.

However, there is an edge case scenario where 1:256 MushroomLayer is needed to count areas of Ocean and Mesa, as 1:256 DeepOceanLayer/BaseBiomesLayer splits up Ocean into Deep_Ocean and Ocean, and Mesa into Mesa_Pleateau_F and Mesa_Plateau. This layer also provides a more accurate representation of climate zones since it is zoomed (1:1024 is still faster for rough generation).

1:256 feels like it is a good maximum scale where it's feasible to count instances of biomes.

This will also be handy for 1.6.4 and older as 1.6.4 generation has repeated LandLayers (a.k.a add island) applied at 1:512/1:256 unlike 1.7.2+ generation. 1:1024 is still useful for 1.6.4 generation since that is where the snow biomes are assigned to in 1.6.4.

[Delvin4519]

Here's an image to show what is meant. As mentioned, Oceans and Mesa biomes are problematic in some cases they need to be combined, or not.