Ensure that WSPR band hopping is disabled when Rig is None

Also added  a new configuration query  method to check if  Rig is None
i.e. a dummy rig.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6629 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

Configuration.cpp

@@ -658,6 +658,11 @@ bool Configuration::is_transceiver_online () const
   return m_->rig_active_;
 }
 
+bool Configuration::is_dummy_rig () const
+{
+  return m_->rig_is_dummy_;
+}
+
 bool Configuration::transceiver_online ()
 {
 #if WSJT_TRACE_CAT