#245 do not display tags of deleted questions

When a question gets deleted, its tags should not be displayed in the
locality page on the left side.
#232 disable buttons when question is deleted

We don't want users to upvote/flag/delete/edit questions when they are
deleted, so the controls are now disabled in a deleted question page.
However, the models still support all the actions if the user is feeling
smart and hacks the request, but it's not such a big deal.