Incorporate use of emix price models into EiEvent (WD16 - 642, 709)

We should expand the EventInfo types within EiEvent to include a price model in addition to the LOAD level types. This can be accomplished in a couple of ways that is completely consistent with the EIQuote service. We can either expand the EventInfo types to include the appropriate references to emix just like we have done in the EIQuote service payloads OR if we find that the price based data model used for EiQuote and EIEvent are identical then I recommend we create a common data model that can be used with BOTH the EIEvent and the EIQuote. This would maintain consistency between the models for prices and how emix is used, but allow prices to be sent using more than one service which I think solves our problem of how emax is used for both priced based DR programs and the newer transactional based interactions described in section 6.

Consider a PRICE EiEvent type. Associate an emix object with the EIEvent payload

We (or profilers) may consider constraining the use of the emix object within this context to keep it simple. If we need anything more complicated or transactional in nature then we use the EIQuote service.