VLTF #255: Proper configuration for pub year facet

So it turns out the trick is to pass an array using map options. So grateful to this post:
http://drupal.org/node/1515756

Here's the documentation from Drupal API for hook_facetapi_facet_info():
http://drupalcontrib.org/api/drupal/contributions!facetapi!facetapi.api.php/function/hook_facetapi_facet_info/7

This commit alone does not tell the entire story. For that you also need to review d641adf87 in ento_solr_config project
https://git.library.cornell.edu/ento_solr_config/commit/d641adf878d0ff69736e6591eea2fadca4ed6f7f