Apply the clearfix hack to .form-actions.

Cartridge floats the buttons inside .form-actions to align them left
or right. This tweak prevents .form-actions from collapsing when
the buttons are floated.
Add a {% block %} to .form-actions in account_form.html for Cartridge
to extend.

This makes it easier for Cartridge to insert an "Order History" button.
Increased margin around buttons in the user panel. Makes it look less
crammed.
Render form errors with a new {% errors_for %} template tag.

This new template tag accomplishes three things:

- Fixes the bug of multiple form error messages appearing when using
{% fields_for %}. This bug was intruduced in [this commit](https://github.com/jerivas/mezzanine/commit/323660db5bee7e21358315c4e247eaa8ee77b034)
and was discovered when [migrating Cartridge to BS3](https://github.com/clemensbasti/cartridge/pull/1)
- Decouples error message rendering from form field rendering, with
the added flexibility of placing the error messages wherever we want.
- Creates a new template (includes/form_errors.html) as the single
location to control form error rendering through all Mezzanine and
Cartridge.
Admin href disqus recent comments to https or http via double slash

Changed how the disqus widget in the admin panel loads its recent
comments. This will fix any errors for loading insecure content.
verbose_names should be capitalized when output

The convention is to always use lowercase verbose_names and capitalize
in the template where necessary.

<https://docs.djangoproject.com/en/1.0/topics/db/models/#verbose-field-names>

> The convention is not to capitalize the first letter of the
> verbose_name. Django will automatically capitalize the first letter
> where it needs to.
Merge
Merge
Added Daniel Lawrence to AUTHORS
Fix a bunch of regressions from namespacing jQuery in admin
css tweaks
Add django 1.6.1 to supported/tested versions.
Move sitemap generation logic for Displayable instances into DisplayableManager.
Added the url/view for displayable_links.js which is then used by TinyMCE to render a list of site links to use.
In TinyMCE, don't convert relative urls to absolute.
pep8 fix