REFS #143 - use BackBee/Utils inside BackBee

* Applied php-cs-fixer
* Removed unused classes (which have been moved to ``utils`` library
* Use ``utils`` library inside project, updated namespaces and composer.json
Is it possible to disable some behavior of php-cs-fixer? To me it's not about being artist or not, it's more about readability. Some times we have to make our own choices.