Implement support for ellipsization mode in wxGrid

Add another wxGrid::DrawTextRectangle() overload, taking wxGridCellAttr
and ellipsizing the string if necessary, i.e. if the fitting mode of
this attribute indicates that we should do it.

Switch the code of all renderers for which it makes sense to use
ellipsization to use the new overload.

include/wx/generic/grid.h

@@ -1160,6 +1160,13 @@ public:
                             int verticalAlignment = wxALIGN_TOP,
                             int textOrientation = wxHORIZONTAL ) const;
 
+    void DrawTextRectangle(wxDC& dc,
+                           const wxString& text,
+                           const wxRect& rect,
+                           const wxGridCellAttr& attr,
+                           int defaultHAlign = wxALIGN_INVALID,
+                           int defaultVAlign = wxALIGN_INVALID);
+
     // ------ grid render function for printing
     //
     void Render( wxDC& dc,