WP-395 Listings missing from the site map
- added listing's images to the sitemap
- added geo location for property to first image
Updating caching lib to allow auth'd caching when flag is set
Even when auth'd, cache this expensive location_list call...
Updates to sitemaps to enhance how the main index is cached and when that cache is circumvented...

Conflicts:
	lib/sitemaps.php
Define this down here, not needed earlier...