[bug 915104] Change wording in "potential answer" email

* Remove distracting link from the title of the question.
* Change wording of "Let us know if this didn't work" to personalize it.
[bug 911583] - list of filtered tags needs separator
Fixed missing link in docs.
[bug 912662] Document badge image requirements.
Add post_migrate receiver to create permissions

This should automatically create permissions for new models we add with
South migrations.
[bug 916550] Update Django to 1.4.8
[bug 910895] L10n of badges.

Adds the localizable Badge fields to the DB_LOCALIZE settings.
[bug 910895] Wrap badge title in gettext.
[bug 914737] Remove Persona doorhanger.

RIP
[Bug 914268] Suggests username during Persona signup

Added suggested username to persona signup.

One interesting case for this method is if the user sign up with
something like: john1@gmail.com and john1 is taken. The suggestion will
be john1[0-9]+

However, I think this is acceptable.

Another note is right now the suggested username gets dropped as a value
of the form prefilled.
Moved suggest_username into utils.py
[Bug 914266] Question archiving, step 1.
[Bug 914266] Question archiving, step 2.