(DONE) Switch Interface

We have MockSwitch that serves no real purpose but testing. Prepare the ground for future “real” switches (see below).

  • Define a Switch interface (switch.h, much like sensor.h)

  • Change MockSwitch to be an implementation of Switch

  • Modify LEDStripeDisplay to use Sensor and Switch (and not MockSensor and MockSwitch)

  • Modify Hysteresis to use Sensor and Switch (and not MockSensor and MockSwitch)