safe dimension

adds a safe dimension, where mobs can not spawn. 

this dimension is meant to be safe, in case the overworld is too dangerous to freely build creatively in. 

primarily for building, to be safe from mob destruction

access to the safe dimension is granted after a player reaches the playerlevel dictated by a gamerule

to enter the safe dimension, one can either use a command (/entersafehouse) or they can use a "panic pearl" 

these pearls are crafted at high expense, but allow access to the safe dimension quickly, so that one does not need to wait the entrance timer. 

as a warning, using the panic pearl in the safe dimension still destroys it, keep this in mind.