Add frequency span query to wide graph class

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6587 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

widegraph.cpp

@@ -252,6 +252,11 @@ int WideGraph::Fmax()                                              //Fmax
   return n;
 }
 
+int WideGraph::fSpan()
+{
+  return ui->widePlot->fSpan ();
+}
+
 void WideGraph::setPeriod(int ntrperiod, int nsps)                  //SetPeriod
 {
   m_TRperiod=ntrperiod;