Partial Fix for #697, plus language update

- When validating the name of a module to be built, check class_exists()
so, at the very least, we don't create a module that shares a name with
a class that's currently loaded by Bonfire and/or Builder
- Display localized module names in the module list (using lang: entries
in the 'name' field of the module's config.php file)
- Move CSS from modulebuilder_form to module CSS file