Remove invalid code path.

Currently, our queues are as large as the number of tweets we can
receive.  Thus, our queue can never be full.
Limit the amount of ranked tweets.

Revert 276c679.
Pointless optimization.
Fix fields.
Undo minimization, store all retrieved (projected) fields.
Refrain from using leaked variable.
Order configurable values.
Read some querying options from config.
Properly score ties.
Fix formatting.
Invert responsibility for item reversal.
Use iteritems in Python 2.x.