Explain verbose level in program options

Core/include/ACTFW/Framework/StandardOptions.hpp

@@ -33,7 +33,8 @@ namespace Options {
         "The number of events to be processed")(
         "loglevel,l",
         po::value<size_t>()->default_value(defaultValue),
-        "The output log level.");
+        "The output log level. Please set the wished number (0 = VERBOSE, 1 = "
+        "DEBUG, 2 = INFO, 3 = WARNING, 4 = ERROR, 5 = FATAL).");
   }
 
   // read standard options