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/osx/carbon/dataview.h

@@ -387,18 +387,6 @@ public:
   {
     return false; // not implemented
   }
-  virtual bool IsReorderable() const
-  {
-    return ((this->m_flags & wxDATAVIEW_COL_REORDERABLE) != 0);
-  }
-  virtual bool IsResizeable() const
-  {
-    return ((this->m_flags & wxDATAVIEW_COL_RESIZABLE) != 0);
-  }
-  virtual bool IsSortable() const
-  {
-    return ((this->m_flags & wxDATAVIEW_COL_SORTABLE) != 0);
-  }
   virtual bool IsSortOrderAscending() const
   {
     return this->m_ascending;