Numerous improvements, including but not limited to:
- Support PostgreSQL v11 (#405, #414 )
- Support Fedora (#393, #408)
- Fix missing or incorrect GUC variables (#403, #406, #407, #411, #415, #417)
- Fix deprecation warnings (#322)
- Verify binary & database versions match, otherwise restart (#418)
- Fix tests to allow "check" runs (#419)
