* Stop setting attributes on class bodies
This behavior has been deprecated since 16.1 and can now be removed in
accordance with our backward-compatibility policy.
* We don't need iterkeys anymore
* Add support for passing a type to attr.ib() and gathering the type from PEP526-style annotations.
* Address review notes.
* More review notes.
* A few more review changes.
* Quick final fix to the changelog.