make services public to avoid error with sf4 (lexik#95)

Allow Symfony ^4.0 (lexik#94)

* Allow Symfony ^4.0 as composer dependency

* Updated Travis matrix to build last possible versions

* Travis build fix

* Require specific phpunit version to avoid failures

* Bugfixed wrong phpunit bin file usage

* Normalize travis testing matrix like other lexik bundles

* Fixed HHVM failure ignore

Version 2.1.0

Version 2.0.1

Version 2.0.0 / SF 2.7+

Paybox Direct Plus support

New semantic of the OptionsResolver's error messages.

Symfony 2.2 compatibility.

Allowed currencies are now configurables.