* fix "existing_package_dict" which wasn't containing metadata_modified (because of the schema in the context) so you never skipped an object.
* fix IntegrityError due to resource revision_id being harvested. No idea why this hasn't caused errors before now.
* "unchanged" is now checked in base instead of ckanharvester - makes sense. Looking at other harvesters, it's normal to return from the import_stage with the value returned from base._create_or_update_package so I've continued with that.
* "unchanged" response is now documented
* better report_status tests in test_queue2.
amercader
David Read