Convert PAN-OS 6.1.0 syslog format to PAN-OS 6.1.1 syslog format.  Closes #8.
Add new fields in PAN-OS 6.1.x syslog format.
Change how report_id is determined now that it is a separate field in PAN-OS 6.1.0 and higher.
Merge branch 'feature/pan-os_6.1' into develop
Update version to v4.2
Merge branch 'release/v4.2' into develop