Rewrote upload queue for better performance
Waiting list is now sorted by queue rank. Clients now carry their rank and
score in member variables, so they can be got in zero time for GUI or EC
transfer. Scores and ranks are updated when a client is added or chosen for
upload, or after 2 min.
Should fix problem from http://forum.amule.org/index.php?topic=17956.0
And client list sorted by queue rank with large queue should greatly gain. :-)
Also fixes the bug that sometimes two clients showed the same queue rank.