Add (optional) Google Protocol Buffers support (example in Tutorial 3).

To use protobuf, run cmake as follows:
cmake -DUSE_PROTOBUF=1 ..
For this, protobuf library has to be installed on the system.

Further changes:
Clean up splitter/merger: default are N-to-1-merger and 1-to-N-splitter.
Fix bug in nanomsg message deallocation.
Setup proper buffer sizes for nanomsg/zeromq via cmake/bash script.
chmod +x for start scripts.

fairmq/zeromq/FairMQMessageZMQ.h

@@ -40,7 +40,7 @@ class FairMQMessageZMQ : public FairMQMessage
     virtual ~FairMQMessageZMQ();
 
   private:
-    zmq_msg_t* fMessage;
+    zmq_msg_t fMessage;
 };
 
 #endif /* FAIRMQMESSAGEZMQ_H_ */