Add PHPUnit as a project dev dependency
Update LICENSE.txt
expliciting README a bit
Merge pull request #5 from Triiistan/add-phpunit-dependency

Add PHPUnit as a project dev dependency
Improve documentation

* Fix typos
* Relative paths are working with busfactor generate command
* Make sure lines don't go above 120 characters
* Improve phrasing
* Explain how to launch tests