feat(modal): modal should close if navigation occurs

You are in a state that modal is open. User clicks back
button on the browser. You use a state manager, for example ui-router,
so page transition happens, without page refresh. Now, you have a
completely different page, completely different state, but you have
modal open.

To prevent this situation, modals are closed automatically on
`$locationChangeStart` Developer may prevent this behaviour by passing
`closeOnNavigation: false` as option.