Add a warning icon.

This uses the standard triangle and "!". There's a standard version
and Retina version.
Move the CommentBarIssueView creation code into ReviewBoxView.

The code to create a CommentBarIssueView was being done inside the
template for the page, adding more script tags and more document.ready
calls.

This code is now created when rendering the ReviewBoxView. It creates
based on data attributes now stored on the element. It's part of an
effort to remove <script> tags in the templates, which will help with
the require.js migration.
Fix HTTP requests on Python 2.5.x.

Python 2.5.x doesn't understand that all HTTP 2xx status codes are
successful responses and not errors. This causes problems when using
Python 2.5 and services like GitHub, which may return 2xx codes.

This fix is not needed for Python 2.6+.

Fixes bug #3043
Merge branch 'release-1.7.x'
Add the 'visible' parameter into the repository API.

This change exposes the 'visible' field in Repository through the API. This can
be retrieved and updated through the API, and the list URL now has a
show-invisible query parameter which will list all repositories, not just the
visible ones.

Testing done:
Ran unit tests.

Reviewed at https://reviews.reviewboard.org/r/4378/