split up Region in MCRegion (Scaevolus) and Anvil formats
extract ChunkCube
Region should not break pry
spec: correct description for format detection
local mca fixture
extract bytes and options handling from Region
move chunk access back into Region
Anvil procrastination
chunks are loaded
configurable chunks count per side
configurable Region#block_size
different Chunk classes
Chunk#new accepts byte Array or raw NBT data