Simplified shutdown hook

areduce was reducing to a value, which is not what you need. The seq
abstraction makes iteration easy.

Also moved the let statement, getting the list of threads at the time of
shutdown.
Added more tests around cache
Remove socket-timeout from mongo-options
Merge pull request #144 from cndreisbach/remove-socket-timeout

Remove socket timeout
Increase version to 0.9.9