Update multi-part features (nanomsg) and various fixes

- Implement nanomsg multipart with MessagePack.
 - Use the MessagePack from FairSoft and handle not found case.
 - Update splitter, merger and proxy devices to handle multi-part.
 - Let FairMQParts.At() return pointer reference (can be used for moving).
 - Add missing const specifier in the message interface.
 - Add transmit kernel size setting to channels (ZMQ_SNDBUF).
 - Remove FairMQBuffer device.
 - Remove old multi-part methods from Tutorial3 example (to be replaced with Parts API).
 - Make callback mandatory for newMsg(data, size, callback).
 - Add missing <vector> include in FairMQSocket.

fairmq/nanomsg/FairMQMessageNN.cxx

@@ -53,7 +53,7 @@ FairMQMessageNN::FairMQMessageNN(const size_t size)
  * create FairMQMessage object only with size parameter and fill it with data.
  * possible TODO: make this zero copy (will should then be as efficient as ZeroMQ).
 */
-FairMQMessageNN::FairMQMessageNN(void* data, const size_t size, fairmq_free_fn *ffn, void* hint)
+FairMQMessageNN::FairMQMessageNN(void* data, const size_t size, fairmq_free_fn* ffn, void* hint)
     : fMessage(NULL)
     , fSize(0)
     , fReceiving(false)
@@ -67,15 +67,10 @@ FairMQMessageNN::FairMQMessageNN(void* data, const size_t size, fairmq_free_fn *
     {
         memcpy(fMessage, data, size);
         fSize = size;
-
         if (ffn)
         {
             ffn(data, hint);
         }
-        else
-        {
-            if(data) free(data);
-        }
     }
 }
 
@@ -97,7 +92,7 @@ void FairMQMessageNN::Rebuild(const size_t size)
     fReceiving = false;
 }
 
-void FairMQMessageNN::Rebuild(void* data, const size_t size, fairmq_free_fn *ffn, void* hint)
+void FairMQMessageNN::Rebuild(void* data, const size_t size, fairmq_free_fn* ffn, void* hint)
 {
     Clear();
     fMessage = nn_allocmsg(size, 0);
@@ -111,14 +106,10 @@ void FairMQMessageNN::Rebuild(void* data, const size_t size, fairmq_free_fn *ffn
         fSize = size;
         fReceiving = false;
 
-        if(ffn)
+        if (ffn)
         {
             ffn(data, hint);
         }
-        else
-        {
-            if(data) free(data);
-        }
     }
 }