Internal Teensy Temperature Sensors

[mbardwell]

Summary

Each Teensy has its own internal temperature sensing unit. On the 3.6 it has to be calibrated (by an external temperature sensor ?). It comes calibrated on the 4.1.

Acceptance Criteria

• do we want this? Why?
• if we do, write unit tests for it
• if we want to integrate it into the larger system, create another issue to do that