HVAC performance heat indicators for seats and left/right dials

[bharmon]

The current state of the repo (commit 82c5bbe) does not show a response when the seat heater buttons are tapped, and the middle dials do not reflect change in the left/right sliders or any other buttons.
I have double checked back through some commits and find that the seat heaters and dials do respond in commits prior to May 4th, Jeff's commit 7498ccb. However, using the bottom buttons still doesn't reflect any changes above as they should.

[bharmon]

Would like to add to this issue that there was a feature we were going to implement that would add an "engine-off" class to the seat heater classes when the engine isn't running, that would indicate that the seat heaters aren't usable unless the engine is running. This class, added to "left_seat_btn" and "right_seat_btn" would reduce the button opacity to barely visible.

[aeichepdx]

Feel free to add that as a separate issue and mark it with the "Type:Feature" label.