Make is easier to compile Bullet/Extras/sph:

1) use $(CUDA_INC_PATH) for CUDA include path
2) avoid using cuda util, but use BT_GPU_SAFE_CALL and BT_GPU_CHECK_ERROR (defined in Bullet/Extras/CUDA/btCudaUtil.h)
3) remove pre-linked glee*.lib, but include glee.c directly

Extras/sph/main.cpp

@@ -583,3 +583,12 @@ int main ( int argc, char **argv )
 
   return 0;
 }
+
+extern "C" {
+	void btCuda_exit(int val)
+	{
+		fprintf(stderr, "Press ENTER key to terminate the program\n");
+		getchar();
+		exit(val);
+	}
+}