Feature request: Make a function to get value of tfStatus

[jhaand]

Thank you for writing this library. It works great.

However I still have the following problem. Since I access the TF-Luna via my own library in a separate file, the library has no access to the Serial device. For a larger project it can be that the Serial device remains out of scope. So if things do not go as planned, I can't do a tfli2c.Print_Status. (See project: House2 TF-Luna HAL )

Feature request:
Provide a function to get the value of tfStatus. And/Or provide a function to copy the message to a char[20] buffer.