Beef up setup.py

- Add more topics
- Add keywords
- Add short summary

Change-Id: I9e1809b02035681e63eff9fbd8085257d0b9c9f5
Reviewed-on: http://review.couchbase.org/27059
Tested-by: Mordechai Nunberg <mnunberg@haskalah.org>
Reviewed-by: Matt Ingenthron <matt@couchbase.com>