Add column role back in TableView itemDelegate

Change-Id: I8e30f3eabf6751fdc55bd3eef8760b0d1b02b060
Reviewed-by: Caroline Chao <caroline.chao@digia.com>

src/controls/TableView.qml

@@ -413,6 +413,7 @@ ScrollView {
                         property int columnIndex: index
                         property int itemElideMode: columns[index].elideMode
                         property int itemTextAlignment: columns[index].horizontalAlignment
+                        property string role: columns[index].role
 
                         function __getValue() {
                             var role = columns[index].role