Enable new callback API

- OnData() channel data handler.
 - ConditionalRun() for devices without incoming data.
 - Header file with common main(), to be extended with getDevice/addCustomOptions.
 - Update examples (MQ/Tutorial3) to use the new API and config.
 - NewSimpleMessage() for simpler creation of small messages (additional copy).
 - Replace SetProperty/GetProperty with fConfig access.
 - Runtime configurable channel names for common devices.
 - Configurable logging interval per channel.
 - FairMQMultiplier for distributing same data to multiple outputs.
 - Cleanup state machine messages.
 - Cmd option to toggle signal handling.
 - Simpler API for send/receive timeouts.
 - Enable --log-to-file.
 - Fix coverity issues, warnings.
 - Various code cleanup and minor tweaks.

fairmq/devices/FairMQBenchmarkSampler.h

@@ -26,33 +26,19 @@
 class FairMQBenchmarkSampler : public FairMQDevice
 {
   public:
-    enum
-    {
-        MsgSize = FairMQDevice::Last,
-        NumMsgs,
-        MsgRate,
-        Last
-    };
-
     FairMQBenchmarkSampler();
     virtual ~FairMQBenchmarkSampler();
 
     void ResetMsgCounter();
 
-    virtual void SetProperty(const int key, const std::string& value);
-    virtual std::string GetProperty(const int key, const std::string& default_ = "");
-    virtual void SetProperty(const int key, const int value);
-    virtual int GetProperty(const int key, const int default_ = 0);
-
-    virtual std::string GetPropertyDescription(const int key);
-    virtual void ListProperties();
-
   protected:
     int fMsgSize;
     int fNumMsgs;
     int fMsgCounter;
     int fMsgRate;
+    std::string fOutChannelName;
 
+    virtual void InitTask();
     virtual void Run();
 };