Stop pulling all of redis into our memory.

This set of changes makes us keep the sums for each category
in their own key, and then when we need to get the scores for
a number of tokens, we fetch only those tokens plus that sum.

The fetching of words is done via redis pipelining for speed.
* Add spec for sums.
* Adjust other specs to account for new ':total' keys
Merge pull request #1 from meekmichael/meek/dont_copy_the_world

Don't copy all of redis into memory