#220 (Jun 2, 2016, 5:35:11 PM)

1. clarified aliases (no warning for duplicates); (detail / hgweb)
2. eliminated pointless alias (no warning for duplicates); (detail / hgweb)
3. avoid warnings on duplicate rules in the given list; (detail / hgweb)
4. avoid stateful operations in virtual bootstrap, which presumably causes occasional crash of drule.ML due to inner syntax pp; (detail / hgweb)

Started by an SCM change