Implement MH-Z19B CO2 Sensor

Need to implement this sensor. 

Python implementation is here: https://pypi.org/project/mh-z19/

and another here: https://www.circuits.dk/testing-mh-z19-ndir-co2-sensor-module/

Look up the PhpSerial class in the include folder??

Here is some z19B data: https://revspace.nl/MH-Z19B

and the older Z19: https://revspace.nl/MHZ19