Allow commenters to change the status of the issues they open.

Until now, only the owner of a review request could change the status of an
issue. A frequently recurring request is to allow the person who originally
opened the comment to do the same--especially to be able to reopen it.

This is an update of Niklas Hambuechen's change at
https://reviews.reviewboard.org/r/3837/

I've updated it to address the original concerns with that change, as well as
streamlined a lot of the code.

Fixes bugs 2713 and 2888.

Testing done:
- Ran unit tests.
- Verified that the "interactive" parameter in the template was correct.

Reviewed at http://reviews.reviewboard.org/r/4380/
Consolidate <script> tags in the diff viewer and reviews.

Every time the browser encounters a <script> tag, it blocks any
downloads or processing of files until that tag has finished. In our
case, it also makes things difficult for require.js, because most of our
<script> tags depend on our objects, which may not be loaded yet.

Now, we just move all the initialization into the same <script> that
sets up the page. That helps code readability and solves a lot of these
issues.

In the case of the diff viewer, I've also moved the scripts-post block
to the end of the file, to put it in page order. Along with that, I
removed the file index at the footer, since it no longer works and will
be replaced anyway.