Fix streaming from holding onto memory

Streaming data should no longer hold onto memory.
However, spinning off new threads is disabled in order for this to work.
Added streaming cancellations back in

I had to manually fool Clojure into garbage collecting our lazy
sequence.
Remove unnecessary cast to string
Merge pull request #160 from cndreisbach/streaming-speed

Fix long streaming
Add a sort before running map reduce
Merge pull request #161 from cndreisbach/sort-map-reduce

Add a sort before running map reduce