- allow reading of only select fields in systemd.journal._reader.Reader
- export sd_journal_test_cursor in systemd.journal._reader.Reader
- export sd_journal_get_usage in systemd.journal._reader.Reader
- allow reading of only select fields in systemd.journal._reader.Reader
- export sd_journal_test_cursor in systemd.journal._reader.Reader
- export sd_journal_get_usage in systemd.journal._reader.Reader