Linup API of wxRadioBox::Show on all ports. Move wxRadioBox::IsValid from wxUniversal to base class (+ GTK which do not use base class) and use it where applicable. Minor source cleaning.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@32325 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk1/radiobox.h

@@ -87,7 +87,7 @@ public:
     wxString GetString( int n ) const;
     void SetString( int n, const wxString& label );
 
-    void Show( int item, bool show );
+    virtual bool Show( int item, bool show = true );
     virtual bool Enable( int item, bool enable = true );
 
     virtual wxString GetStringSelection() const;
@@ -142,6 +142,10 @@ protected:
     // common part of all ctors
     void Init();
 
+    // check that the index is valid
+    // FIXME: remove once GTK will derive from wxRadioBoxBase
+    inline bool IsValid(int n) const { return n >= 0 && n < GetCount(); }
+
 private:
     DECLARE_DYNAMIC_CLASS(wxRadioBox)
 };