- support Python 3.6, refactor CI/test setup, increase test coverage
- refactor BidirectionalMapping, BidictBase, OrderedBidictBase,
FrozenBidictBase, and subclasses
- move frozenorderedbidict into _frozen and looseorderedbidict into _loose
- register bidict as a virtual subclass of MutableMapping rather than
inheriting from it directly. This makes it clearer that it does not use any
of the concrete generic methods that MutableMapping provides.
- improve performance and flexibility of frozenbidict and
frozenorderedbidict hashing
- docs, including new type-hierarchy.png diagram
- rm unused imap, ifilter, izip_longest from compat, add PYPY
- update to latest versions of dependencies
- restore benchmarking on travis
jab