- Adjust factory default behavior to match Options object default behavior.
- Simplify code in the process using null coalescing.

- Pull the facet config from the options object so we don't have to rely on hard-coded config names in as many places.

- Note that this breaks in IE8 and earlier; we have chosen to drop IE8 support.

- Make all JSON responses into keyed arrays so that they can be e.g. extended without breaking compatibility.
- Get rid of the redundant status field in the responses in favor of HTTP status codes.

- This protects against trying to render an empty catalog login template resulting from ILS connection failure.

- Resolves VUFIND-1287.