Thermocouple range indication

[charlespax]

The data stream from the T100 will indicate if the thermocouple is disconnected to is measuring a voltage out of the thermocouple range. This should be handled gracefully in the commandline tool. The tool does not necessarily have to directly present what the T100 outputs.

The T400 uses four dashes as described in the manual to indicate when the temperature is out of range. We should probably stick with the same thing for the T100 unless there is a compelling reason to do otherwise.

Reference:

• T100 Thermocouple measurement range discussion
• LCD: Display indicates disconnected thermocouple
• Serial: Data string indicates disconnected thermocouple

Firmware discussion: PaxInstruments/t100-firmware#10

[charlespax]

Moving to next milestone.

[charlespax]

When the thermocouple is unplugged the reading is 9999999. A user could filter this from their results. Moving this to post-MVP (minimum viable product).