Improved setbiome filter, added replacebiome filter

In the setbiome filter theres a few typos with the new 1.7 biomes, and they were not in alphabetical order, making them hard to find. Also added a replacement chance for randomized biome placement, which adds  nice irregular grass patterns. Also adds a replacebiome filter.

Both changes are showcased here: https://www.youtube.com/watch?v=EhZCRddbxe8