Need to fix the DB backend for the following issues:
- Document or add to config: objectstore.backend = db
- Dump tool says (invalid) TRUE, it checks for 0xFF but SQLite stores 0x01.
- There are printf in the code.
- No log handler is set in the calling functions, will thus use stderr.
- Fix memory leak in test code.
- There are DB::initialize() and DB::shutdown() but no one is using it. Should they be used?