Added simple utility to get last URL modification
Added simple utility to get last URL modification

- This will be used by the scraper tasks to determine if documents need
  to be refetched and reprocessed.

cityofsomerville/citydash,codeforboston/cornerwise,codeforboston/cornerwise,codeforboston/cornerwise,cityofsomerville/citydash,codeforboston/cornerwise,cityofsomerville/cornerwise,cityofsomerville/citydash,cityofsomerville/citydash,cityofsomerville/cornerwise,cityofsomerville/cornerwise,cityofsomerville/cornerwise