Code review comment for lp:~allenap/launchpad/just-comment-on-question-bug-114710

The first change in this branch is to make the "Add comment" button
always appear. I just followed sinzui's patch in the bug report and
then updated tests. I've done other stuff in this branch, so I've
broken out just the changes that account for this fix here:

  http://pastebin.ubuntu.com/277696/

The other stuff was adding a few cancel links, changing some of the
form action wordings, and fixing a bit of lint:

  http://pastebin.ubuntu.com/277724/

To test:
  bin/test -vvt lp/answers

The only lint reported is bogus.