Behat 3 upgrade

Upgrade to Behat 3

To do:
- [x] update the `behat.yml` to reflect changes on Behat 3
- [x] change profiles to use suites (more suites instead of more profiles)
- [x] change travis to use the new profiles and suites to test

Actually see this working:
- [x] do a test PR
- [x] pass on that PR (https://github.com/ezsystems/ezpublish-community/pull/182)
2.0.0 stable seems to be out so @\dev can be dropped, unless you depend on the fix in master: https://github.com/Behat/Symfony2Extension/compare/v2.0.0...master