* Make _CountingAttr empty metadata unique
Issue #278
* Correct st.none().map() to st.builds()
* Add 'real' and 'force coverage' tests for not None metadata
* Add changelog for pr 280
* Correct import order in tests/test_make.py
* Add back coverage force test
* Remove debug print from test/utils.py
* 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
* Restore hash to validators.
* Restore Attribute.default and Attribute.validator.
* _AndValidator is hashable now. Test validator hashability.
* Add in_ to validators.__all__.
If this method is defined for a class, it will get executed at the end
of ``__init__``. Previously, there was no way to extend what was
done during ``__init__`` when using ``@attr.s``.
Hynek Schlawack