Add mode dependent working frequencies

Working frequencies are mode dependent  and a reset to defaults button
has been added.

Also re-factored much of the model  and item delegate code to simplify
several  of the  model  implementations. Introduced  a single  routine
called from main to register the custom types with Qt.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@5453 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

Radio.cpp

@@ -2,7 +2,6 @@
 
 #include <cmath>
 
-#include <QMetaType>
 #include <QString>
 #include <QChar>
 #include <QDebug>
@@ -14,19 +13,6 @@ namespace Radio
 {
   namespace
   {
-    struct init
-    {
-      init ()
-      {
-        qRegisterMetaType<Frequency> ("Frequency");
-
-        qRegisterMetaType<Frequencies> ("Frequencies");
-        qRegisterMetaTypeStreamOperators<Frequencies> ("Frequencies");
-
-        qRegisterMetaType<FrequencyDelta> ("FrequencyDelta");
-      }
-    } static_initaializer;
-
     double constexpr MHz_factor {1.e6};
     int constexpr frequency_precsion {6};