Add font colour support to wxFontPickerCtrl.

Currently this is only really implemented under Windows, just as the colour
support in wxFontDialog, but make the API available under all platforms for
consistency.

Closes #11614.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76160 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/fontpickerg.h

@@ -35,6 +35,12 @@ public:
         Create(parent, id, initial, pos, size, style, validator, name);
     }
 
+    virtual wxColour GetSelectedColour() const
+        { return m_data.GetColour(); }
+
+    virtual void SetSelectedColour(const wxColour &colour)
+        { m_data.SetColour(colour); UpdateFont(); }
+
     virtual ~wxGenericFontButton() {}