Follow-up of d97cce34096043b019e818a7fb98c0f9f073704c and 7d3fe36c626a3268413eb86d37920f132eb4a54f.
Backport of 35319bf12ccefe1911588493484160aa49208f89 from master
Thanks Aymeric Augustin for shepherding the DEP and patch review.
Thanks Marten Kenbeek and Tim Graham for contributing to the code.
Thanks Tom Christie, Shai Berger, and Tim Graham for the docs.
To improve consistency, sample URL names that had underscores
in them now use dashes instead. That excludes URL names that
have some relation to the code, such as those generated by
the admin.
Thanks guettli for reporting this.
The code examples should now work correctly.
The `get_context_data` method in the examples was changed when
necessary to adopt a singular style (get context with super(...),
add the extra keys to the dict then return it).
Thanks to Remco Wendt for the initial report and to Tim Graham
for the review.
This also updates all dependent functionality, including modelform_factory
and modelformset_factory, and the generic views `ModelFormMixin`,
`CreateView` and `UpdateView` which gain a new `fields` attribute.
Credit goes to @SystemParadox. Originally developed at #DjangoCon Europe
but wasn't tested enough to merge in.
For history, please see https://github.com/pydanny/django/pull/4
