#862: Removes default shortcut from Fl_Shortcut_Button

- the current UI for fallback/default/original shortcut was
confusing, so I remove it until we find something better. I
kept the values so we can reinstate a better interface without
changing the API.

FL/Fl_Shortcut_Button.H

@@ -33,9 +33,12 @@ public:
   Fl_Shortcut_Button(int X,int Y,int W,int H, const char* l = 0);
   void value(Fl_Shortcut shortcut);
   Fl_Shortcut value();
+#if 0
+  // Default shortcut settings are disabled until successful review of the UI
   void default_value(Fl_Shortcut shortcut);
   Fl_Shortcut default_value();
   void default_clear();
+#endif
 };
 
 #endif // Fl_Shortcut_Button_H