Several FairMQ fixes and improvements:

- FairMQ: add possibility to poll on multiple channels.
- FairMQ: include command channel when polling on blocking calls (for unblocking without termination).
- FairMQ: move signal handler inside of FairMQDevice class (call FairMQDevice::CatchSignals() in the main function).
- FairMQ: add 'bool CheckCurrentState(statename)' (instead of 'GetCurrentState() == statename' that cannot be thread safe).
- FairMQDevice: add 'InteractiveStateLoop()' method that can be used to change states from the command line.
- FairMQDevice: add automatic transition to IDLE state if Run() exits without an external event.
- FairMQDevice: implement device reset.
- FairMQDevice: use unordered_map for device channels.
- FairMQChannel: improve address validation for channels.
- FairMQChannel: add ExpectsAnotherPart() method to check if another msg part is expected (old approach still works).
- FairMQ: remove invalid transition from the run files.
- FairMQFileSink: disable ROOT termination signal handler.
- Tutorial3: spawn xterm windows from start scripts without overlapping for better visibility.
- FairMQ Examples: update protobuf test and move its files to a common directory.
- FairMQStateMachine: improve feedback on invalid transitions (more readable).

fairmq/examples/1-sampler-sink/FairMQExample1Sink.cxx

@@ -30,7 +30,7 @@ void FairMQExample1Sink::Run()
     {
         FairMQMessage* msg = fTransportFactory->CreateMessage();
 
-        fChannels["data-in"].at(0).Receive(msg);
+        fChannels.at("data-in").at(0).Receive(msg);
 
         LOG(INFO) << "Received message: \""
                   << string(static_cast<char*>(msg->GetData()), msg->GetSize())