py-furl: updated to 1.2

Furl v1.2:
Added: Path segment appending via the division operator (__truediv__()).
Changed: Bump orderedmultidict dependency to v1.0.
Changed: Check code style with flake8 instead of pycodestyle.
Changed: Percent-encode all non-unreserved characters in Query key=value pairs,
including valid query characters (e.g. '=', '?', etc). Old encoding:
?url=http://foo.com/; new encoding: ?url=http%3A%2F%2Ffoo.com%2F. Equal
signs remain decoded in query values where the key is empty to allow for, and
preserve, queries like '?==3=='.

(adam)