permafrost biome

Changelog:

-There is now the new mob the ice spike. (won't spawn naturally)

-The ice wizard will now have a chance to summon ice spikes around him when hurt.

-There are now barrels in the ice.

-There are now powder snow patches generating in the biome.

-There is a new block weak ice and these also generate in the biome.

-And some other minor changes.