fix some out-of-bounds error in the OpenCL rigid body pipeline

re-enable an OpenCL/gpu rigid body example (box-box stack)

examples/OpenCL/rigidbody/GpuSphereScene.h

@@ -0,0 +1,27 @@
+#ifndef GPU_SPHERE_SCENE_H
+#define GPU_SPHERE_SCENE_H
+
+#include "GpuRigidBodyDemo.h"
+
+class GpuSphereScene : public GpuRigidBodyDemo
+{
+public:
+
+	GpuSphereScene(){}
+	virtual ~GpuSphereScene(){}
+	virtual const char* getName()
+	{
+		return "BoxOnSphere";
+	}
+
+	static GpuDemo* MyCreateFunc()
+	{
+		GpuDemo* demo = new GpuSphereScene;
+		return demo;
+	}
+
+	virtual void setupScene(const ConstructionInfo& ci);
+
+};
+
+#endif //GPU_SPHERE_SCENE_H