init() argument sets initial URL, instead of not-found URL as documented

[asazernik]

Calling router.init("/some/url") will:

• Set the URL to "/some/url" on page load no matter what the initial URL was, contrary to the documentation
• Not set the URL to "/some/url" when setRoute("/some/bogus/url") is called with "/some/bogus/url" having no handler defined.