New method which returns active class if route is matched

In Bootstrap the `active` class is used in a number of ways, but not necessarily the `a` tag itself. For example, the navigation elements place the `active` class on the `li` tag instead. This function saves Bootstrap developers from having to use:

    <li class="{{ Active::is('page*') ? 'active' : null }}">

And instead can simply use:

    <li class="{{ Active::classes('page*') }}">