pybullet, more robust multi-server connections

Windows shared memory: allow to use custom key.
Improve GUI performance on Windows, submit letters in text as a batch (fewer draw-calls)
quadruped.py: first try to connect to SHARED_MEMORY, if it fails (<0) use GUI
increase Chrome about://tracing json export capacity (press 'p' in Example Browser)
UDP physics server: add --port and --sharedMemoryKey command-line arguments
PhysicsServerExample: add --sharedMemoryKey command-line option (for VR example too)
ExampleBrowser: sleep a few milliseconds if rendering is too fast, use --minUpdateTimeMicroSecs=0 to disable

examples/SharedMemory/PhysicsClientSharedMemory.cpp

@@ -207,7 +207,7 @@ bool PhysicsClientSharedMemory::connect() {
             m_data->m_isConnected = true;
         }
     } else {
-        b3Error("Cannot connect to shared memory");
+        b3Warning("Cannot connect to shared memory");
         return false;
     }
 #if 0