Some improvements

* Added contributors list to `composer.json` (linked to github contributors graph)
* Improved Behat context
* Fixed/Cleaned/Tested configure options handling
* add `--default` option to `install` command
I don't think you should force the verbose output all the time. Scenarios needing to assert the verbose output should pass the ``-v`` flag instead. It would be much more readable when looking at the scenario, because the scenario would show that it is the verbose output