PT-1349 - Updated documentation.

  Calling something out as "risky", without making clear what the risk is or
  offering people downstream some guidance on how to mitigate the risk feels
  alarmist. This is more verbose, but will hopefully be more constructive for
  whoever bumps into this during the mongo2mysql work.

 	modified:   api_petitions.module
PT-1349 - Removed @todo. This has been resolved.

	modified:   api_petitions.module
PT-1349 - Updated outdated documentation.

	modified:   petitions_data/classes/Petition.inc
PT-1349 - Fixed formatting on API petitions resource index mock response.
PT-1349 - Fixed improperly thrown exception.
PT-1363 - Fix php undefined index notice.

  api_services_responses.module
PT-1363 - Added debug mode and pretty print utility.

  signatures_queue.admin.inc
  signatures_queue.module
PT-1363 - Added verbose logging during signature creation.

  modified:   api_signatures.inc
PT-1363 - Fixed bug breaking petition signing.

 	modified:   receive_new_signatures.inc
PT-1363 - Enhanced new pretty printing log formatter a little.
PT-1363 - Fixed a couple of watchdog() invocations.
PT-1347: Fixed petition token values, so they can be populated in
emails.
MISC - Remove dependency on overlay module.
pt-1349 petitions_data Adding removed as a visible status.  Though in its current state, this will never appear in the api because the api is only returning public petitions.
pt-1349 wh_petitions Updating doc blocks to be more meaningful.
pt-1349 wh_petitions Removing WH_PETITION_STATUS_FLAGGED as signable or public.  This status corresponds to removed, which should be neither signable, nor public.
pt-1349 petitions_data Adding details to docblock for isPublic and isSignable.
pt-1352 petitions_api/api_petitions Adding a check for exception->getData as Mongo sometimes throws errors that lack this method.
pt-1352 petitions_data Fixing handling for stacking status request filters like isPublic, isSignable and status=.
pt-1352 wh_petitions Adding function to return array of all possible statuses.