PyBullet: added preliminary DART and MuJoCo backend files, MuJoCo can loadMJCF, stepSimulation and getBasePositionAndOrientation, DART is empty.

PyBullet: add 2d biped example.,

examples/SharedMemory/dart/DARTPhysicsServerCommandProcessor.cpp

@@ -0,0 +1,39 @@
+#include "DARTPhysicsServerCommandProcessor.h"
+
+
+DARTPhysicsServerCommandProcessor::DARTPhysicsServerCommandProcessor()
+{
+}
+	
+DARTPhysicsServerCommandProcessor::~DARTPhysicsServerCommandProcessor()
+{
+
+}
+
+bool DARTPhysicsServerCommandProcessor::connect()
+{
+	return false;
+}
+
+void DARTPhysicsServerCommandProcessor::disconnect()
+{
+	
+}
+
+bool DARTPhysicsServerCommandProcessor::isConnected() const
+{
+	return false;
+}
+
+bool DARTPhysicsServerCommandProcessor::processCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes)
+{
+	return false;
+}
+
+bool DARTPhysicsServerCommandProcessor::receiveStatus(struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes)
+{
+	return false;
+}
+
+	
+