Prevent JavaScript errors on the Manual Updates pages.

The Manual Updates page tried to load the JS catalog, needed in order to
expose gettext() for the other scripts being loaded. That path wasn't
explicitly allowed, resulting in HTML being sent back as the script
contents, causing the browser to show some errors.

We may want to consider just blocking off all script loading. That will
require blocking extensions as well, though, and possibly daeling with
other corner cases. In the meantime, allow the JS catalog to be loaded.

Reviewed at https://reviews.reviewboard.org/r/5800/
Fix the styling of titles in the admin UI.

Titles in the admin UI were previously styled by the 'h1.title' rule,
which we replaced with '.box-title'. However, the admin UI doesn't use
boxes in the same sense as the rest of the UI, due to Django's built-in
styling.

This adds an explicit rule for titles in the admin UI, allowing them
once again to use the same styles as our other boxes.

Reviewed at https://reviews.reviewboard.org/r/5801/
Fix fetching original and patched files through the web API.

The handlers for getting original/patched files in the API were
expecting a URL parameter that doesn't exist. It would always attempt to
fetch using the draft filediff resource, instead of intelligently
choosing between that and the published filediff resource.

By using the correct URL parameter name, and using that parameter
correctly, we can fetch the original/patched files correctly.

Reviewed at https://reviews.reviewboard.org/r/5804/
Remove the Pygments runtime dependency checks.

We have some really old code (Makefile days) for checking if syntax
highlighting can be enabled, based on having Pygments, and having a
minimum version of it. This code, in combination with some other code,
ends up creating some ugly and unnecessary circular dependencies between
parts of the product that only appear if you start importing certain
modules first.

These days, we have actual dependencies that get installed with the
product. This check is no longer useful, and causes more harm than good.
This change removes the check and all calls.

Reviewed at https://reviews.reviewboard.org/r/5811/
Condense some unnecessarily verbose code in reviewboard.admin.

Due to changes made over time to the admin widget code, we ended up
having some code in reviewboard.admin.signals that didn't really belong
there. A signals.py file should be fairly minimal and contain actual
signals, but this one had just signal handlers that were called from
reviewboard.admin itself.

This change just removes the file and moves that code directly into
reviewboard.admin, to keep things simple and consistent.

Reviewed at https://reviews.reviewboard.org/r/5812/
Bump django dependency to 1.7.13.

Picking up the latest security release for Django.
Merge branch 'release-1.7.x' into release-2.0.x
Bump django dependency to 1.6.5

Picking up the latest security release for Django.