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==.