* added possibility to set Range, to enable/disable Autocalibrate and to calibrate maually ( see Datasheet v 1.2 : https://www.winsen-sensor.com/d/files/MH-Z14A.pdf
* Update MHZ.cpp
* Update MHZ.cpp
* Update MHZ.h
added calibrate Span, for complete functionality but commented out , due to professional use (req. constant atmosphere with 2k, 5k or 10k ppm CO2.).
corrected the bugs in MHZ.cpp also.
* Update MHZ.cpp
Added comments for Sensors with specific firmware.
Co-authored-by: Christoph Schultz <christoph@schultz1-christoph.de>