Implemented primary keys in contracts analysis views.
Simplified urls of contracts analysis.
Improved entities crawler to cleaner interface.
Refactored contracts crawler.

Improved interface, code and docstrings.
Prepared staging to tests on new database.
Added timeout of 5s to all requests.
Added Timeout exception handler.
Improved handling of timeout, adding a logging call.
Made minor improvements to the crawler.
Updated docs with latest version of the contracts crawler.
Made general improvements to the docs.
Improved docstrings of law analysis.
Fixed computation of percentage of laws without text from 1986.
Migrated models.Entity validation to Django forms API.
Added nv.d3 and first graph using nv.d3.js.
Major refactor of graphs to use nvd3.js.
Merged branch 'nvd3' into staging.
Added nvd3.js to git.
Migrated crawler data validation to Django forms and fields.
Added logging support to categories builder.