fix missing fields in rbn_cache, add timings

set/debug rbntimer will show how long a queue takes to process (remember
that this includes sending data out to users).
set/debug rbnskim shows the process of determining the "one true frequency" of
a spot, by running a weighed "auction" of all the spotters's performance
in previous "auctions". A spotter's frequency "score" can be between 5 and -5
(good -> bad) and that is added to each version of the frequency that is
sent by the RBN. The frequency with the highest score is the one posted.
It is the 'QRGScore' in the "progress" spot message.