Stero Sid 2.0.7: Arduino 2.x and license update

A small update to Stereo Sid:

1. Fix lack of LICENSE (merge from original Cyberernesto upstream)
2. Fix library.properties and arduino lint pass, to be able to be included inside arduino library manager
3. New professional CHANGELOG file

Note: StereoSID will work only for Arduino UNO R1-R3 and AVR-based chipset.
We are evaluating a support to new Arduino WiFi R4