Adds 404/500 support via pass-thru to Angular

### Notes
- `/abc` will be redirected to `/#/abc`.  This attempts to let angular pick up the route, and if failing, pass along to its `errorController` as a 404.
- `/fail` is a specific (test) error route that triggers a server error, that is then caught by the server side error handler.  The error handler redirects the error to `/#/error/:url`, which is also handled by `errorController`, but with a `server-error.html` template