Fixed links syntax error in docs homepage.
Added MultiForm and MultiModelForm classes.
Make NonBraindamagedErrorMixin use error_class

Form users can override the error_class (this is useful for rendering)
on a form.
Use NON_FIELD_ERRORS constant instead of hardcoded value

In the future, django team can decide to change the key associated to
non fields errors. They'll do so by changing NON_FIELD_ERRORS constant.

With this fix, django team won't be able to break betterforms.
Added csrf_exempt argument for form_as_fieldsets.
Fixed Changlist typo.
Merge remote-tracking branch 'origin/nonbraindamagederrormixin-cleanup'
Merge branch 'multiform'

* multiform:
  Added MultiForm and MultiModelForm classes.
Drop support for Django 1.3.
Added support for Python 3.
Added cleaned_data to MultiForm.

This should improve compatibility with things like
django.contrib.messages.views.SuccessMessageMixin.

Reviewed-By: Antoine Catton <acatton@fusionbox.com>
Added support for Django 1.6.
Merge branch 'py3'

Reviewed by: Scott Clark <sclark@fusionbox.com>
Allow, render legend attributes on fieldsets
Betterforms has no BaseForm class?
Add legend feature to documentation
Test fieldset legend rendering