added a const version of wxColourData::GetColour()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@14489 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/cmndata.h

@@ -36,7 +36,8 @@ public:
     void SetChooseFull(bool flag) { chooseFull = flag; }
     bool GetChooseFull() const { return chooseFull; }
     void SetColour(const wxColour& colour) { dataColour = colour; }
-    wxColour &GetColour() { return dataColour; }
+    const wxColour& GetColour() const { return dataColour; }
+    wxColour& GetColour() { return dataColour; }
 
     // Array of 16 custom colours
     void SetCustomColour(int i, const wxColour& colour);