Commons Written Answers scraping/parsing script.

UK Parliament Written Answers are now in a new database-driven website. This site has a nice search and RSS feeds, and XML data will be available, but for now we still need a bit of scraping to fetch the data. Ever so slightly simpler than the past, though :)
Yeah, I set params to `None` at the end of the first loop, so that's okay. I liked the opportunity to drop urllib as an import, but I guess the cache-in-error code won't be deleting the right URL any more if it's page one that goes wrong, so I should probably change it back.