Import data from senators.
Import committees for senators.
import votes
Created vote importer.

* Added support to save binary streams in the cache.
* Added several utility methods to Importer class.
Updated documentation for vote importer.
Fixed README styles.
Added support to determine whether an entry exists in the cache or not.

* Modified VoteImporter to heavily use cache if possible.
Updated README.
Import commitees members.
Fixed bug in bill importer.

* Date filter had a bad month value.
Added support to store items with a role.

* Updated documentation.
* Normalize people position field.
Updated version up to 1.2.0