Post type tweaks

- parse_query now uses the post_type value as the array key like the other facets do.
- $post_type object is used in every case it can be for the various facet values to make the code easier to read.
- $terms->hits was switched to $term->hits since $terms->hits doesn't actually exist.
- removed wp_count_posts from parse_query which was left in but not being used.