[Bug 760744] Update bleach and py-wikimarkup.

Upgrade Bleach to v1.1.4 (latest stable) and py-wikimarkup to a
compatible version.
[bug 767967] Auto-refresh page when reindexing
[bug 768226] Implement m2m product field

This adds a products field to wiki Document which is a many-to-many
with the Products table.

It was tricky because we used "products" in the form and then had
some code to move things to tags. I had to rename that form field
to "product_tags" in order to fix a bunch of issues that adding
the model field created. Then I had to carry the product_tags form
field name change through the code base.
[Bug 701385] "Update" questions only when answered.

Previously questions would have the `updated` field set to
`datetime.now()` when ever `Question.save()` was called, unless
`no_update=True` was specified. This caused it to move to the top of
question listings, which is not desired. The only time a question should
be moved to the top is when it is answered, so this changes the default
behvior to *not* update the `updated` field unless `save` recieves a
parameter `update=True`. The `Answer` model has been similarly modified.

Tests have been added/modified to assure that this is the case, and I
looked over existing code to make sure anything that interacted with
`Question.updated` was adapted.
[bug 775671] Fix migration 151

I'm not sure why this works on production databases, but doesn't
work on brand new databases, but this one line fixes it. The problem
is that a fresh database doesn't have a django_content_type for
redirect, yet.
Bug 772448 - Filter username from AoA results
bug 775332 - a11y: bold sender names in message listing

a11y: Make sender names bold in message listing on SUMO
[bug 776014] Admin page for investigating issue

This adds a thrown-together admin page to investigate the possibility
that live indexing isn't working correctly. It shows the last 50 wiki
documents indexed side by side with the last 50 wiki documents with
revisions that were approved. I think showing these side by side
would show whether there were things that weren't indexed that should
have been and may shed some more light on what's going on.
[bug 766534] Make AoA stats more motivating
Fix the way answered tweets are counted

We should not simply count the number of replies, we should actually
count the number of tweets that have replies.
Add note about engine=innodb to migration docs
[bug 777087] Set AoA replies goal to 175.
[bug 768875] Add topic models
[bug 776014] Add redirect column to admin page

Makes it easier to see which pages are redirects. We're not supposed
to index redirects.
Fix .gitignore regarding static directory
[bug 775224] Populate products table

* tweaks products table to have an image field
* adds a placeholder image for the image field
* populates initial products in the table
[bug 768876] Add M2M topic field.

This adds a topics field to wiki Document which is a many-to-many
with the Topics table. Includes migration.
[bug 771716] Remove bucketed search view

This removes all the bucketed search view code and most of the code it
required. There are some straggling pieces, but we can remove those
at a later date and under other bug numbers.

This removes the esunified waffle flag and the e= url parameter in all
the search urls.
Update search docs

This updates the search docs removing the text about bucketed and
unified search views and all that.
[bug 770108] Add AAQ link to closed threads