Alter the queue so that each queue item stores the scheduled time of the next delivery. This keeps the query for

queued items simple. We no longer group by posturl; as the queue update function will only keep one item per destination
scheduled for shorter term processing. Others (multiple queued items for a single destination) will be scheduled for
delivery far into the future and only delivered if the hub responds to the "active" or short term queue item.

boot.php

@@ -52,7 +52,7 @@ define ( 'PLATFORM_NAME',           'hubzilla' );
 define ( 'STD_VERSION',             '2.1' );
 define ( 'ZOT_REVISION',            '1.2' );
 
-define ( 'DB_UPDATE_VERSION',       1187  );
+define ( 'DB_UPDATE_VERSION',       1188  );
 
 define ( 'PROJECT_BASE',   __DIR__ );