Animal terrain finisher

Adds animals to cChunkDesc entity list on chunk generation.

resolves #1595 

Note: animals do not spawn, either the list does not get refreshed and sent to world, or the mobs spawn too far away and are removed shortly after.
This won't work well, the noise functions return the same number for the same input coords. You should add `Tries` to the equation, usually it's done by adding it to one of the coords.