Better integration inside other libraries

Added notes and an empty constructor/populated begin method to allow this library to be more easily called inside of other libraries.

Fixed timeout values

Fixes the time-out values for the ParseInt and ParseFloat to be -9999. This was the intended behavior all along, but at some point those functions changed in the stream library and the identically named functions within SDI-12 intended to "hide" the stream functions ceased to be calle.

Initial Release

The first "official" release of this interrupt-based SDI-12 library for AVR and SAMD Arduino boards.