fix #889. User Defined Rollups were accidentally broken by move to 4 batch rollup classes.
Merge dev into feature/889-UDR-fixes
Merge pull request #916 from SalesforceFoundation/feature/889-UDR-fixes

fix #889. User Defined Rollups were accidentally broken by move to 4 bat...
Merge dev into feature/purge-on-delete-true