Refs #4 - Extract ControllerTestCase class.
Refs #4 - Write basic tests for SocialLoginController::login().
Refs #4 - Test that state is set in OAuth URL.
Refs #4 - Add some tests for SocialLoginController::callback().

Also move getServiceProvider method to SocialLoginService.
Refs #4 - Correct return types in doc blocks.
Refs #4 - Test that expected handler method called for callback action.
Refs #4 - Test redirect URL when various exceptions are thrown.
Refs #4 - Test that github and facebook callback methods are implemented.
Refs #4 - Fix class case issue.
Merge pull request #4 from synapsestudios/feature/4-social-login-controller-tests

Add tests for social login controller