WIP: replcae the kbtree with khash, we don't need the tree features (yet, if ever) and hash is faster; add a most-recently-used stash for contexts as it's highly likely that worker threads will do many operations with the same shape/signature of session/cursors/tables/config and that path can be lock-free as well making it much faster (one would hope); somewhere something is stepping on read-only ErlNifBinary data and so a crc check is failing and causing the runtime to abort, that's the latest item to find/fix.