Times are much improved. Nice improvements in speed when my disk
doesn't have the directory hashed. Sequential access for filling
the blockMap and md5Map results in a quiet purr from the disk
and cold times are down from 90 seconds to 6 seconds. They don't
have make_unique yet and shared_ptrs are so easy to make.

This this needs major cleanup, but it appears to work correctly now.
Logging was fixed so it is actually threaded from all sources -
I think.