tweak Mini Cheetah URDF/MTL

use /tmp/timings on Linux/Mac as default location to save profile timings (when you press 'p' in example browser)
fix in Graphics Server Example when rendering is disabled

examples/ExampleBrowser/OpenGLExampleBrowser.cpp

@@ -257,7 +257,11 @@ void MyKeyboardCallback(int key, int state)
 			}
 			else
 			{
+#ifdef _WIN32
 				b3ChromeUtilsStopTimingsAndWriteJsonFile("timings");
+#else
+				b3ChromeUtilsStopTimingsAndWriteJsonFile("/tmp/timings");
+#endif
 			}
 		}