Edit template displays hidden fields

I have a form that needs to use some hidden fields (`forms.HiddenInput()`). The edit template displays these fields. 

One possible fix is to change the edit template (https://github.com/caktus/django_bread/blob/develop/bread/templates/bread/includes/edit.html) a little. Right after this line:

```
{% for field in form %}
```

add this:

```
{% if field.field.widget.input_type != 'hidden' %}
```
