Database hookups

Sessions and items are hooked up to database.  Not ideally yet, but we can get there.  I changed the format of the item and session a bit to have it fit the database better, you can push back on that if you want.  Popularity will need a special query to get it into the items.  Also, look on cchdev for the needed changes to context.xml (db resource).  There are tests for the database read and write, but they are disabled because they require a database and I moved to JNDI for defining that.

Ivan, can you look it over to make sure it isn't going to break everything?  Local testing seems to work ok.