Fix small typo
Bug fix for model formsets and inline formsets

When rendering a formset using a FormHelper with a layout set, hidden
fields were not being rendered unless explicitly mentioned in the
layout. Using the new `render_hidden_fields` attribute in helper, we can
now make sure all hidden fields of all formset's forms are rendered.

This could fix #143, or be a different bug.

Added a test case for avoiding regressions.
Removing deprecation warning for Django 1.5 and upper
Making test pass in Django 1.5 and previous versions

Some refactoring and clean up going on
Merge branch 'patch-1' of git://github.com/vially/django-crispy-forms into dev
Bumping version to 1.2.7