Python-interface

- Added support for Python 3.7. (https://github.com/ssanderson/interface/pull/23)
- Added `Interface.from_class`. (https://github.com/ssanderson/interface/pull/14)
- Updated setup.py to use PEP 508 version markers (https://github.com/ssanderson/interface/pull/13/)

- Added `interface.default`, which allows users to define default implementations of interface methods.
- Added a backport of `functools.wraps` in python 2 that sets `__wrapped__` on wrapping functions.

Note:

Version 1.3.0 was released with a bug in the implementation of `default`. Users are encouraged to use 1.4.0 instead.

Adds support for requiring `property`s as part of an interface definition.

Adds support for Python 2.7.