Update for PSR-4

You can now update the directories for better readability.
Everything in FormTranslationBundle folder can go directly in form-translation-bundle.

And more readable if you put folders : Builders, DependencyInjection, Form, Model and Resources in src folder
If you do that, update your autoload : "Elao\\Bundle\\FormTranslationBundle": "src/"
Fix InvalidArgumentException in Travis

Fatal error: Uncaught exception 'InvalidArgumentException' with message 'A non-empty PSR-4 prefix must end with a namespace separator.
Merge pull request #4 from mathias-strasser/patch-1

Update for PSR-4