[WIP] Enable support for FOSUserBundle 1.x and 2.x

This PR is an attempt to make HWIOAuthBundle compatible with FOSUserBundle 1.3 and 2.0. This is based on [#163](https://github.com/hwi/HWIOAuthBundle/pull/163). There are still some obstacles like the dynamically setting the alias which doesn't yet work.

Any suggestions is appreciated.