0.5.0

Start this changelog
Added some more comments throughout
Fixed dependency on django-filebrowser by wrapping it in an exception check
Handle get_absolute_url returning None
Use HEAD requests for checking external URLs
Handle HREF="#" correctly
Cleaner display of hashtag links in reports
Handle 'Bad Status Line' responses from remote servers.
Don't spawn a thread if running from tests as this prevents the new thread from seeing the same database transaction as the parent thread
Fix some tests from prior to the big refactor. nb Tests are still incomplete and many are broken :(
document filebrowser dependency

