Unified print library

[Avamander]

Due to all the differences between different micro-controllers this library works on the current method of printing debug, warning and error messages is rather clunky and ugly, often causing confusion. Because of that I propose that a universal serial printing wrapping library is created. (Also see nRF24/RF24#189 (comment))

I opened identical issues in other RF24 family libraries: https://github.com/TMRh20/RF24/issues/322 nRF24/RF24Network#103