SimpleWorkflow service support for cancellation - EUCA-9622

Support is added for actions supporting cancellation of activities and
workflows:

 * RecordActivityTaskHeartbeat
 * RequestCancelWorkflowExecution
 * RespondActivityTaskCanceled
 * RespondDecisionTaskCompleted
   - CancelWorkflowExecution
   - RequestCancelActivityTask

EUCA-9622
Merge remote-tracking branch 'origin/dev/sjones/EUCA-9622' into testing