Implement exact-active class for exact url matches - resolves #68

[Joucke]

        $this->menu = Menu::new()
            ->setExactActive(true)
            ->link('/', 'Home')
            ->link('/people', 'People')
            ->link('/people/sebastian', 'Sebastian')
            ->setActive('/people/sebastian');

now renders to

            <ul>
                <li><a href="/">Home</a></li>
                <li class="active"><a href="/people">People</a></li>
                <li class="active exact-active"><a href="/people/sebastian">Sebastian</a></li>
            </ul>

Tests are in

• MenuSetActiveTest@it_can_set_items_exact_active
• MenuSetActiveTest@it_only_sets_exact_active_on_exact_url_match
• MenuSetActiveTest@it_can_render_a_custom_exact_active_class

Spatie\Menu\ExactUrlChecker is a clone of Spatie\Menu\ActiveUrlChecker, and only returns true if the url is an exact match.

[Joucke]

@sebastiandedeyne Please let me know if I need to improve this. Also, is the CI problem caused by something I did, or is a setting messed up somewhere?

[sebastiandedeyne]

Looks great! I think we should just always add the class when doing the active check though, don't really see the point in maintaining a flag for it.

[Joucke]

@sebastiandedeyne should I let you know I added requested changes, or are you notified automatically? No idea how this works from owner pov, just asking :)

[sebastiandedeyne]

Perfect, thanks!