* Initial low level interface for thread crash reporting (and management).
* Add a member version of isClusterRole()
* isolate heartbeat thread creation to new StartHeartbeatThread(). create heartbeat thread even if not a cluster or if an agent.
* update runDBServer() and runCoordinator() to shutdown more quickly by polling isStopping() at additional locations.
* copying updates from different branch / PR
* basic thread crash logging. Not yet tied into Agency arangod or have any specific threads posting crashes
* make Supervision thread a CriticalThread
* sandwich CriticalThread between Thread and other classes to create long term, repeating thread crash reporting.
* restore code lost upon branch update relating to new startHeartbeatThread() function
* add CriticalThread.cpp to build
* add new runAgentServer() function to loop for Agents. Make Heartbeat thread derive from CriticalThread.
* remove debug line
Jan
Frank Celler
Matthew Von-Maszewski