Update voltage in co-optimization

[mnblonsky]

There is no way to update the house voltage when co-optimizing. (Co-optimization is iterating within a single time step, which can be done with Simulator.update_model.) Voltage can only be updated from the schedule_inputs, which only gets read in Simulator.update_inputs, not in Simulator.update_model.

There's also a question of whether "inputs" are significantly different from "controls". We can have both in the schedule, and it seems like both should be modified in co-optimization.

For now I think the plan is to remove the schedule_inputs argument from Simulator.update, have control_signal include all inputs and controls, and pass that to Simulator.update_model. This could involve a few other changes:

• Rename controls to be consistent with schedule names.
• Change control_signal from a 2-level dict to a 1-level dict (see Simulator.start_sub_update)
• Use consistent names for schedule names and result names (e.g. "Ambient Dry Bulb" vs. "Temperature - Outdoor").
• If we use consistent names, we can enumerate them. This may improve simulation speed when creating the schedule, parsing controls, and generating results.