[bug 693988] Stop caching previews.

[bug 693304] Make AoA more tolerate of bad data.

* Be more careful checking data from metrics before using it.
* Try to allow partial data (e.g. no contributors).
* Handle extraneous "null" values.

[bug 679806] Don't count outdated articles as done on Overview l10n d…

…ash.

[bug 689552] Make Firefox 7 the new default.

[bug 686153] Upgrade to Django 1.3.1

[bug 685111] Search assumes tags inherit.

Update the Sphinx config so it pulls tags off the *parent* document,
if it exists, so that translations inherit their parents' tags.

[bug 681807] Exclude archived articles from Related Articles.

[bug 681807] Exclude archived articles from Related Articles.

[bug 675628] Add Firefox 7 to Help With dropdown on next.

[Bug 677962] Add permissions for ImportantDate