Internal constant missing - Sys Range Offset

[ajsb85]

Application note AN4545
VL6180X basic ranging application note

Other libraries that support this settings:

https://github.com/sparkfun/SparkFun_ToF_Range_Finder-VL6180_Arduino_Library
https://github.com/pololu/vl6180x-arduino

[ladyada]

pull requests welcome!

[tekktrik]

I've really wanted to try my hand at I2CDevice actually, I can take this!

[tekktrik]

Hardware to test is on the way, will check in when I've got it working or otherwise need help. Then I'll submit the PR!

Branch with proposed change in my fork: https://github.com/tekktrik/Adafruit_CircuitPython_VL6180X/tree/feature/add-manual-offset

[tekktrik]

@ajsb85 I submitted a pull request, let me know if this fits how you're using it!

[tekktrik]

Resolved by #22