OClCollMeshEngn: Use shouldAcceptRequests stop/finalize() pattern

This makes the stop() method capable of synchronously stopping all
engine/server-type async services which don't act in a self-moved
fashion but instead wait for a request.

stimBuffApis/livoxGen1/openClCollatingAndMeshingEngine.h

@@ -13,6 +13,7 @@
 #include <CL/cl.h>
 #include <asynchronousLoop.h>
 #include <callback.h>
+#include <spinLock.h>
 #include <user/stimulusFrame.h>
 #include "stagingBuffer.h"
 #include "frameAssemblyDesc.h"
@@ -59,9 +60,9 @@ private:
 		StagingBuffer& assemblyBuff, StagingBuffer& collationBuff,
 		collateKernelCbFn callback);
 
-	void stopCompactKernel();
-	void stopCollateKernel();
-	void stop();
+	void compactKernelComplete();
+	void collateKernelComplete();
+	bool stop();
 
 public:
 	// Get kernel execution durations in milliseconds
@@ -80,16 +81,15 @@ private:
 	cl_program collateProgram;
 	cl_kernel slotCompactorKernel;
 	cl_kernel collateKernel;
-	bool isSetup;
 
 	// OpenCL buffers
 	cl_mem clAssemblyBuffer;
 	cl_mem clCollationBuffer;
 
 	// State tracking
-	bool compactIsSetup;
+	SpinLock shouldAcceptRequestsLock;
+	bool shouldAcceptRequests;
 	bool compactIsRunning;
-	bool collateIsSetup;
 	bool collateIsRunning;
 	cl_event currentCompactKernelEvent;
 	cl_event currentCollateKernelEvent;
@@ -155,15 +155,8 @@ private:
 		size_t globalWorkSize,
 		void (CL_CALLBACK *eventCallback)(cl_event, cl_int, void*),
 		const char* kernelName,
-		bool& isSetup,
 		bool& isRunning)
 	{
-		if (!isSetup)
-		{
-			std::cerr << __func__ << ": engine not set up" << std::endl;
-			return false;
-		}
-
 		if (isRunning)
 		{
 			std::cerr << __func__ << ": already running, call stop() first"