Updated to include creation of category averages.

Basic code to create user-specific category averages is included, but is
terribly inefficient (estimate 3,000+ hours to complete a run).
The yelpSubmissionFormat function reads IdLookupTable.csv and returns
ordered array containing submission format [
[user_id_1,business_id_1],[user_id_2,business_id_2] ... ]
Removing YelpSubmissionWriter