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/ParticlesOpenCL/main.cpp

@@ -0,0 +1,51 @@
+/*
+Bullet Continuous Collision Detection and Physics Library, http://bulletphysics.org
+Copyright (C) 2006 - 2009 Sony Computer Entertainment Inc. 
+
+This software is provided 'as-is', without any express or implied warranty.
+In no event will the authors be held liable for any damages arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose, 
+including commercial applications, and to alter it and redistribute it freely, 
+subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "ParticlesDemo.h"
+#include "GlutStuff.h"
+#include "GLDebugDrawer.h"
+
+#include "btBulletDynamicsCommon.h"
+#include "LinearMath/btHashMap.h"
+
+
+// standard utility and system includes
+//#include <oclUtils.h>
+// Extra CL/GL include
+//#include <CL/cl_gl.h>
+
+
+GLDebugDrawer	gDebugDrawer;
+
+int main(int argc,char** argv)
+{
+    // start logs
+//    oclSetLogFileName ("appSpheresGrid.txt");
+//    oclLog(LOGBOTH, 0.0, "appSpheresGrid.exe Starting...\n\n"); 
+	
+	
+	ParticlesDemo ccdDemo(argc, argv);
+	ccdDemo.initPhysics();
+	ccdDemo.getDynamicsWorld()->setDebugDrawer(&gDebugDrawer);
+
+#ifdef CHECK_MEMORY_LEAKS
+	ccdDemo.exitPhysics();
+#else
+	return glutmain(argc, argv,640,480,"Bullet Physics Demo. http://bulletphysics.com",&ccdDemo);
+#endif
+	
+	//default glut doesn't return from mainloop
+	return 0;
+}