v2.0.0

Changed

• Passing a pre-initialised Session to PageIterator constructor
  is now mandatory
• HashtagIterator must be provided a rhx (it is infered for
  ProfileIterator)

Fixed

• API changes made by Instagram ca. April 2018 (excluding logging in / out)
• Calling operator.length_hint on PageIterator objects will no longer
  cause duplicate server queries.