Move some code from Branches/OpenCL to trunk, related to threading and OpenCL:

Added Demos/ThreadingDemo showing how to use the cross-platform btThreadSupportInterface under Windows.
Added Demos/ParticlesOpenCL showing how to run the NVidia particle demo under OpenCL implementations by AMD, NVidia and MiniCL (CPU)

Demos/SharedOpenCL/btOclUtils.h

@@ -0,0 +1,24 @@
+
+#ifndef BT_OCL_UTILS_H
+#define BT_OCL_UTILS_H
+
+#ifdef USE_MINICL
+	#include <MiniCL/cl.h>
+#else
+	#ifdef __APPLE__
+		#include <OpenCL/cl.h>
+	#else
+		#include <CL/cl.h>
+	#endif __APPLE__
+#endif
+
+//#define oclCHECKERROR(a, b) btAssert((a) == (b))
+#define oclCHECKERROR(a, b) if((a)!=(b)) { printf("OCL Error : %d\n", (a)); btAssert((a) == (b)); }
+
+
+void btOclPrintDevInfo(cl_device_id device);
+cl_device_id btOclGetDev(cl_context cxMainContext, unsigned int nr);
+cl_device_id btOclGetMaxFlopsDev(cl_context cxMainContext);
+char* btOclLoadProgSource(const char* cFilename, const char* cPreamble, size_t* szFinalLength);
+cl_device_id btOclGetFirstDev(cl_context cxMainContext);
+#endif //BT_OCL_UTILS_H