Patch from Hartwig and me for implementing reorderable dataview columns. Works on OS X and GTK+, breaks OS X a litte

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@50919 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/dataview.h

@@ -328,7 +328,7 @@ public:
     virtual void SetResizeable( bool resizeable );
     virtual void SetHidden( bool hidden );
     virtual void SetSortOrder( bool ascending );
-
+    virtual void SetReorderable( bool reorderable );
 
     // getters:
 
@@ -347,7 +347,8 @@ public:
     virtual bool IsHidden() const
         { return (m_flags & wxDATAVIEW_COL_HIDDEN) != 0; }
     virtual bool IsSortOrderAscending() const;
-
+    virtual bool IsReorderable() const
+        { return (m_flags & wxDATAVIEW_COL_REORDERABLE) != 0; }
 
 private:
     int                      m_width;