investigate behavior during .backup #70

To properly back up the steve.db, SQLite says to use the .backup meta command. Apparently, this locks the whole database.

ACTION: investigate the locking behavior, and the app's behavior when it is locked. Does it block, or does it fail?

If it fails (likely with an exception/error that indicates the lock), then maybe add some retry behavior to await release of the lock. And/or investigate SQLite Write Ahead Logs (WAL) and if that can mitigate the problem. And/or other strategies for backup during continuous operation.