only show add comment link if logged in

add post_id/type to new comment link

add new_post_comment_url helper to dry params
tidy up validations on question
update todo with more stuff
return head 401 if wrong user calls accept_answer

Since this is only ever called from javascript the redirect is
not needed
add node about pundit spec blocking rspec 3
update gems

pick a pundit fix to upgrade to rspec 3 now
Merge branch 'master' into comments

Conflicts:
	Gemfile