Tstat equipment

[jmaguire1]

Creating an abstract class for thermostatic loads, including HVAC and water heating. Making lots of other changes too.

Work that is complete and in progress:

• Create ThermostaticLoad class
• Replace on/off "Mode" variables and outputs with "On Fraction" variables and outputs
  • Water heating
  • HVAC
  • Other loads
  • Move update_mode_times to update_results and update reset_time
  • Incorporate load fraction and other ext controls in on fraction
• Update Equipment.update_model function to always call run_internal_control
  • Modify function
  • Create new variables for external controls
• Add new tstat mode to prevent overshoot
  • Add method in run_internal_control
  • Test for water heating
  • Test for HVAC
• Update Simulator.update function to consolidate control_signal and schedule_inputs (maybe wait on this)
  • Modify function
  • Change/merge controls and schedule names
  • Maybe replace current_schedule with individual variables
  • Update example scripts and docs
• Remove duty cycle control functions, and related inputs and outputs in docs
• Remove Mode related inputs and outputs in docs
• Add new inputs and outputs in docs
  • prevent_overshoot
  • on fraction outputs

Still need to review issues and see which this will address.

• Reference the issue your PR is fixing
• Assign at least 1 reviewer for your PR
• Test with run_dwelling.py or other script
• Update documentation as appropriate
• Update changelog as appropriate

[jmaguire1]

@mnblonsky: what happened was #140 was based on ev1.7, which I closed since it'd been merged. Didn't lose any of your commit history or anything, I think this should just supersede what was there.