0.2.0 release

• add CRC check in request(), thanks to DaveDavenport
  • failing CRC indicates communication error.
• added MTP40F_INVALID_CRC
• update unit test
• add section about multi device / multiplexer to readme.md
• minor edits examples

0.1.2 release

update readme.md

0.1.1 release

fix getGasConcentration (#3)

- fix **getGasConcentration()** status handling
- update readme.md
- improve readability some parameters
- add (SoftwareSerial) schema to several examples
- add **MTP40F_REQUEST_FAILED** (error handling is still to do)
- add default value to **setAirPressureReference(apr = 1013)**
- add default value to **setSelfCalibrationHours(hours = 168)**
- update examples

0.1.0 release

Update README.md