[fixed] sibling array route configs

now you can configure your routes like this:

```js
var extraRoutes = [<Route/>, <Route/>];
var routes = (
  <Routes>
    <Route/>
    {extraRoutes}
    <Route/>
  </Routes>
);
```

closes #193
[added] <DefaultRoute> component

Also, changed behavior of routes with no name, path, or children so
they act as default routes. <DefaultRoute> is essentially just sugar.

Fixes #164
Fixes #193