Deprecate getlanguagebar

The function getLanguageBar isn't doing anything that a developer can't do themselves directly in a template. It doesn't support users that aren't using the blade template engine; in fact it flat out breaks if you use Twig or some other engine. Therefore removing it in v1.0 will make supporting the package that much easier.  

I've added an example for creating a language selector in the README.

Also, no objections in https://github.com/mcamara/laravel-localization/issues/61

Please merge pull request https://github.com/mcamara/laravel-localization/pull/69 before this one.

Tag v0.13.0