Actually take passed in args into consideration
Link topic and org pages to new email signup
Link to "all (announcements|publications)"
Fix tests to use new functionality
Make sure email signups are in announcements JSON
Remove govdelivery_url field
Include policy activity URLs in notify feeds
Mop up remaining method reference
Link policy activity to email signup page

The signup bit isn't functional yet. Forthcoming.
Stop overwriting params

Because params is global, modifying it in place clobbers it for
everything else using it on the page. We should use a local copy instead.
Use policy.slug
Remove admin tests for govdelivery_url
Style updates

Thanks @tekin
Link topical events to right signup params
Add policies to URL extractor
Add policies to title extractor
Show policy checkbox on signup page
Custom validation rule for policies
Spelling
Test for policy validation