Added ASL 2.0 License
Added CHANGELOG.md
Quick script to run all tests.
Fix precission issue.
Fader would never reach the final desired tone.

E.g. a fade from 0 to 10, would never reach 10, but only 9.99 or
whatever (closer to 10 the greater the number of slots).
Revamp colour_fader unit tests.
Fix unittest api deprecation warning.