Adding a change log

[dknx01]

For a better communication, what changed in a version compared to others. a README.md file would be very helpful,

[merzilla]

I would prefer a CHANGELOG.md or change.log file either. There are some auto-generate changelog things around which might help.
Just found
https://github.com/lob/generate-changelog
or
https://github.com/github-changelog-generator/github-changelog-generator
Also i guess Dmitry knows how to do it with just using git command.