Move username_allowed, write basic test

This moves username_allowed from passwords to forms which seems better.
It also adds a basic test that we can flesh out at some point to make
sure things are kosher.
Fixed bug where localized string was compared to unlocalized.
This script might fix some of our TB woes.
[bug 979317] Move AAQ product/topic picker to bottom.
[bug 979311] Replace Get Started with Other in AAQ.
[bug 978662] Chunk the twoots to save memory.
[bug 979331] Remove fancy click to edit for AAQ title.
[bug 979434] Fix _check_username

The argument passed into _check_username can sometimes be None because
it's coming out of cleaned_data, but wasn't valid. Because of that,
username_allowed returns False and then everything goes to straight to
hell.

This commit fixes that.
[bug 980262] Remove AAQ link from header during AAQ.
[bug 979328] Shrink the AAQ progress bar.
[bug 979319] Re-style the article list in AAQ.
[bug 966978] Add support for FxMetro in AAQ.
Revert "[bug 966978] Add support for FxMetro in AAQ."

This reverts commit eb479285dda93dba5104fe2a7356e340ff83661f.
[bug 726941] Allow users to close their account