Allow Kelvin as CTC100 unit

[hp-peti]

No description provided.

[trappitsch]

Good catch, for completeness, Fahrenheit should probably be added as well as:

"\xb0F": u.fahrenheit,

One more fun fact: The manual states

If the units are set to an empty string,
thermocouple readings are shown in millivolts and RTD and thermistor readings are shown in
ohms, even if the sensors have a custom calibration curve with declared units (see the “Custom
calibration” section).

This means that the dimensionless units actually return mV... This is probably for the user to catch, since a dimensionless value is not really physical either way for this device.

[scasagrande]

When you get a chance can you update your branch with the latest main