Use @show_object_detail for viewing blog posts
Fix title when viewing priate messages
Fix ordering of private messages

It looks wrong on the dev site but it's fine in production ... idk

Anyway, this makes the tests pass (which I'll commit ASAP)
Improve status code check in _ViewTest

Now checks for the 302 response for tests that require login_first, and
assumes that the expected response code is 200 afterwards/otherwise.
Add tests for private-message-related views
Add tests for blog-post-related views
Add default ordering to BlogPost model
Check for correct blog post order in NewsIndexTest
Add check_context method to NewsItemTest