add re-usable createGraphicsSphere method in GpuDemo.

introduce and use maxContactCapacity (needs to be fixed in various other contact kernels)
implement sphere versus trimesh
disable new/sequential GPU batching (only uses 1 thread in a warp, slow but works on NVIDIA/Apple OpenCL)

opencl/gpu_sat/host/ConvexHullContact.h

@@ -53,6 +53,8 @@ struct GpuSatCollision
 
 	cl_kernel				m_bvhTraversalKernel;
 	cl_kernel				m_primitiveContactsKernel;
+	cl_kernel				m_findConcaveSphereContactsKernel;
+
 	cl_kernel				m_processCompoundPairsPrimitivesKernel;