Move default state out of run block

`$scope.go()` inside the top-level run block will increase test complexity as
a mock template cache would need to be set up for each test that uses `$scope`
regardless of whether it depends on a template.

UI Router currently uses a state using an empty `url` as the default state,
see:

https://github.com/angular-ui/ui-router/issues/182
https://github.com/angular-ui/ui-router/issues/174#issuecomment-19330523

Since we're setting up the layout in a parent, abstract state, redirect to the
*real* index using `otherwise()`.