zlib-rs provides the same performance as zlib-ng with minedmap, while
reducing the amount of C code and avoiding the external build dependency
on CMake.
Get rid of the arbitrary bin/lib split and instead move as much as
possible into the bin crate, which becomes the main crate again.
The types and NBT handling are moved into separate crates, so they can
be reused by nbtdump and regiondump.