Add Rename Attribute item to column header menu.
Selecting the Rename Attribute item brings up a dialog which allows the new name to be entered.
Improved Rename Attribute feature
-- Localizable menu item strings
-- Don't show column header menu if all items are disabled
-- Don't allow duplicate attribute names
-- Don't allow empty attribute names
Implement Delete Attribute feature on case table column header menu.
Merge branch 'renameAttributeFeature'

Implement Rename Attribute and Delete Attribute features.