[2.2][Security] AuthenticationException enhancements

Bug fix: semi
Feature addition: yes
Backwards compatibility break: yes
Symfony2 tests pass: [![Build Status](https://secure.travis-ci.org/asm89/symfony.png?branch=issue-837)](http://travis-ci.org/asm89/symfony)
Fixes the following tickets: #837
License of the code: MIT

This PR adds the functionality discussed in #837 and changes the constructor of the `AuthenticationException` to match that of `\Exception`. This PR will allow developers to show a translated (save) authentication exception message to the user. :)

*Todo:* 
- Add some functional test to check that the exceptions can indeed be translated?
- Get feedback on the current English messages