start mongo integration
thread tweaking
Merge branch 'master' into mongo

Conflicts:
	src/twitter_stuff/main.clj
	src/twitter_stuff/parsing/parse_tweet.clj
	src/twitter_stuff/utils/couch.clj
debug mongo integration
pull hashtags out into top-level field, debug mongo sharding
update tf-idf for mongo, clean up mongo, fill out screen-map docstring
tf-idf, starting post-processing