Basic framework in place to create feature extractors.
Cleaned up imports.
Merge pull request #1 from beets/master

Rotten Tomato data munging
Added cast feature extractor
RT sql dump

gunzip rt_ratings.sql.gz
cat rt_ratings.sql | mysql -uroot cs221movies
Small movie filter update

Limit to movies with revenue in USA specifically (otherwise we’ll get
worldwide, aus, uk, etc)