Added a new filter, 'Sentinel\hasAccess'

Noticed they have added to the original filters that you had, at http://laravelsnippets.com/snippets/sentry-route-filters. I went ahead and made it work similar to the modifications that you added to `Sentinel\inGroup`. 

Also, since you can apply multiple filters to any routes, do we really need to repeat this line of code `if (!Sentry::check()) return Redirect::guest(Config::get('Sentinel::config.routes.login'));` in each filter? Instead, when applying filters you could simply use `'Sentinel\auth|Sentinel\hasAccess'`.