Condition check before ending the main thread.

Make sure the main thread waits for the child thread with the Run() method.

* Add this at the end of your Run() method for each device:
```
boost::lock_guard<boost::mutex> lock(fRunningMutex);
fRunningFinished = true;
fRunningCondition.notify_one();
```
* Then you must replace the `char ch; cin.get(ch);` in your main() function with:
```
boost::unique_lock<boost::mutex> lock(processor.fRunningMutex);
while (!processor.fRunningFinished)
{
    processor.fRunningCondition.wait(lock);
}
```

fairmq/run/runMerger.cxx

@@ -124,8 +124,12 @@ int main(int argc, char** argv)
     merger.ChangeState(FairMQMerger::SETINPUT);
     merger.ChangeState(FairMQMerger::RUN);
 
-    char ch;
-    cin.get(ch);
+    // wait until the running thread has finished processing.
+    boost::unique_lock<boost::mutex> lock(merger.fRunningMutex);
+    while (!merger.fRunningFinished)
+    {
+        merger.fRunningCondition.wait(lock);
+    }
 
     merger.ChangeState(FairMQMerger::STOP);
     merger.ChangeState(FairMQMerger::END);