Enable Widgets be used by to_formidable() for extra-fields

[brunobord]

Review

• Tests
• Docs/comments
• CHANGELOG.rst Updated
• rebase w/autosquash
• Delete your branch

[alexdashkov]

The code looks good to me, but I do not really understand how we can implement it in the HTML/JSON rendering. Could you explain it to me or/and add some examples?

[brunobord]

Could you explain it to me or/and add some examples?

Using FormidableForm instances is the most used way to test Formidable objects and their behaviour outside of their links to business-logic objects. In order to test rendering, we then needed to use the to_formidable() method.
This to_formidable() method creates a whole set of instances. Not using regular formidable fields or widgets would lead to partial data storage (missing items, missing parameters) at runtime.
I wanted to make sure that this part of the django-formidable library API (not the HTTP API, the software API) wouldn't be a blocker when using an external field.

[syldb]

LGTM, thanks!