CraftManager code manipulations
Memory usage by shreds and world tuning.

Those functions are defined:
World::SetBlock - put some block to xyz and activate it if possible.
World::PutBlock - put some block to xyz.
World::PutNormalBlock - put normal block to xyz.

Shred::SetBlock, Shred::PutBlock, Shred::PutNormalBlock are the same
except xyz here are local (in shred).