Better errors.
Clean up. Fixed an error message.
Only going to put the values into an mmap'd file. The mmap for buckets
was getting to complex.

The idea is to put the files on disk and reference them via mmap, that
way we can keep the state of the metainformation in the AOL file and the
actual values in the values file.
Don't really need this yet.
Checkpointing before I forget what I am doing.

Halfway through values-on-disk refactor. Taking a break. Does not
compile.
Compiles. Tests probably don't pass. Horrifying.
Segfaults. Always segfaults. mmap() is getting the wrong size for things
because size_t is unsigned or something.