Notice of Filing and Immediate Effectiveness of a Proposed Rule Change To Permit the Exchange To List Options on the Cboe Volatility Index ("VIX options") on a Group Basis and Make Conforming Changes Throughout the Rules, Change the Minimum Increment for VIX Options Listed Under the Nonstandard Expirations Pilot Program (if the Exchange Lists VIX on a Group Basis), and Make Nonsubstantive Changes