extract (and expand and clean up and document) the header window implementation used inside the generic wxDataViewCtrl in a separate wxHeaderCtrl class which could be reused in (generic) wxListCtrl and, most importantly, wxGrid later

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@57093 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/dataview.h

@@ -323,6 +323,8 @@ public:
 
     virtual void SetReorderable( bool reorderable );
 
+    virtual void SetFlags(int flags) { SetIndividualFlags(flags); }
+
     // getters:
 
     virtual wxString GetTitle() const;
@@ -338,6 +340,8 @@ public:
     
     virtual bool IsReorderable() const;
 
+    virtual int GetFlags() const { return GetFromIndividualFlags(); }
+
     // implementation
     GtkWidget* GetGtkHandle() { return m_column; }
     GtkWidget* GetConstGtkHandle() const { return m_column; }