* add sdbclient.UpdateUptime; update args for sdbclient.CreateEntryIfNotExists
* add auditcount to node stats; restructure statdb.CreateEntryIfNotExists
* add noop mock sdbclient
* add the ability to create a node in statdb without "default" stats
* update statdb.CreateEntryIfNotExists
* take fewer args for sdbclient.CreateWithStats/FindValidNodes
* add sdbclient.UpdateAuditSuccess
* update sdbclient.Update so that all fields are updated when called (reduce args)
* update error checking in statdb.Create
