Adding multiple transports support & other fixes:

- Avoid polling when only one input channel is used.
 - Send only handles for shared memory transport.
 - Avoid waiting in the rate logger thread when nothing to log.
 - Hide warnings from generated files
 - Fix #483

fairmq/nanomsg/FairMQTransportFactoryNN.cxx

@@ -16,9 +16,11 @@
 
 using namespace std;
 
+static FairMQ::Transport gTransportType = FairMQ::Transport::NN;
+
 FairMQTransportFactoryNN::FairMQTransportFactoryNN()
 {
-    LOG(INFO) << "Using nanomsg library";
+    LOG(DEBUG) << "Transport: Using nanomsg library";
 }
 
 FairMQMessagePtr FairMQTransportFactoryNN::CreateMessage() const
@@ -55,3 +57,8 @@ FairMQPollerPtr FairMQTransportFactoryNN::CreatePoller(const FairMQSocket& cmdSo
 {
     return unique_ptr<FairMQPoller>(new FairMQPollerNN(cmdSocket, dataSocket));
 }
+
+FairMQ::Transport FairMQTransportFactoryNN::GetType() const
+{
+    return gTransportType;
+}