Fix bug in budget_bucketized and turn on caching.

Also add a tool to analyze generated features for proposal.
Merge remote-tracking branch 'upstream/master'
Budget feature by year

The feature value is difference of budget from average budget for the
year.
Merge pull request #12 from beets/master

Generalized budget feature extractor
Merge branch 'master' into justinc-nn
Added a little more testing code
Added basic runner for full pipeline