making write and read methods public instead of protected (feature request)

[MileBuurmeijer]

It would, for my use case, be awesome if the read and write methods defined in TMCStepper.h become public. I wanted to read register configurations from a JSON file and then write these to the stepper driver. And directly read back for the readable ones. Currently, these are protected and can not be accessed outside the TMC stepper classes. I made them public in my test of TMCStepper.h and work fine. For the rest is TMCStepper a very good library.