Code cleanup

[Gummibeer]

• remove unneeded else and also validate the config url
• remove unneeded else and return false in every non success case
• remove a bit of complexity and don't throw an exception if all exceptions are catched and returned as false
• return just booleans, don'T throw exceptions - just log them

[Gummibeer]

Except of these the code climate is very good: https://codeclimate.com/github/invisnik/laravel-steam-auth :+1:

The only missing things for me are tests (phpunit, travis and so on)