PT-976 - Added petition_id to dummy data field in validate signature record for signatures_validated_queue.

	modified:   modules/custom/signatures_queue/classes/SignaturesQueue.inc
PT-976 - Created new workflow shunts.
PT-961 - Added shunt dependency to signatures_queue.
PT-1003 - Created Drush command to invoke signature workflows.
PT-1003 - Refactored signature workflow invocation.

Conflicts:
	docroot/profiles/petitions/modules/custom/signatures_queue/signatures_queue.module
PT-1003 - Replaced a couple of forgotten strings with constants.
PT-961 - Fixed a little refactoring oversight.
PT-961 - Automated shunt declaration.