feat(routing): use longer path first

This patch makes the following example (from the angular.js tutorial
step 7) work.

```dart
views.configure({
  'phonesList': ngRoute(
    'path': 'phones',
    'enter': (\_) => ...
  ),
  'phoneDetail': ngRoute(
    'path': 'phones/:phoneId',
    'enter': (\_) => ...
  )
});
```