Added a new class called Sitemap that is used to generate a series of XML documents representing the URLs of metacat documents following the sitemap protocol. The Sitemap class extends TimerTask so that it can be scheduled to run once a day or so. New configuration options were added to metacat.properties to control where the sitemaps are written and hw often they are updated. By default we do it once a day, as more often is overkill for search engines.
Included a JUnit unit test to test the Sitemap generation functionality.
Included changes to MetaCatServlet to schedule the Sitemap task the first time Metacat is called.