in the user view for bills, catch when an invalid bill type is in the URL
twostream: when the inner page raises a Http404, eat the exception and return other valid user-specific page content
no longer have to hide the login link on the blog template because it's populated dynamically by AJAX
another try at eating exceptions when a tracker is added to a list twice, violating a uniqueness constraint
show the go-ad-free ad less often
index bill text using GPO bill text (via congress project) rather than pdftotext extracted text layers because the extracted layers have word-wrapping with hyphenation which breaks search