smo::Mind instance now global; track & manage JOLT state in Mind

We moved the instance of smo::Mind to global scope. I suppose we'll
only support one instance of Mind per SMO process at least for now.

We now track the state of Mind threads' JOLT-waiting. This allows us
to centralize the Mind thread shutdown logic. Mind::finalizeReq()
now takes care of all Mind thread shutdown state logic by tracking
whether Mind threads need to be JOLTed first before being told to
exit.

smocore/include/mind.h

@@ -3,6 +3,7 @@
 
 #include <config.h>
 #include <thread>
+#include <functional>
 
 #include <director/director.h>
 #include <simulator/simulator.h>
@@ -12,9 +13,11 @@ namespace smo {
 class Mind
 {
 public:
+	Mind(void) : threadsHaveBeenJolted(false) {}
+
 	void initialize(void);
 	void execute(void);
-	void finalize(void);
+	void finalizeReq(std::function<void()> callback);
 
 public:
 	std::thread directorThread;
@@ -23,8 +26,13 @@ public:
 
 	director::Director director;
 	simulator::Simulator canvas;
+
+private:
+	bool	threadsHaveBeenJolted;
 };
 
+extern Mind mind;
+
 } // namespace smo
 
 #endif