Fix DB creation & upgrade; automated testing. **Important bugfixes:** Creating a new database didn't work in v0.4. Neither did upgrading from dbversion 1 databases (2–7 were OK, though). (Note that dbversions don't match Podist version numbers; v0.4 uses dbversion 8, for example) **New features:** Now displays the feed number when adding a new feed, so you can immediately pass that as "catch" (etc.)'s -f argument. **Internals:** Not have GitLab CI running and have a few more tests; that's how the above bugs were found, for example.