Update to the latest typeshed:
    
    - typing: update 2 to match 3 on Sequence and Container
    - builtins: Reversible is redundant when Sequence is already present
    - Add __version__ to _ast.pyi.
    - add Python 2 stubs for ast, tokenize
    - Improve Python 2 stub for abc; _weakrefset stub.
    - Update shlex.pyi
    - Update random.pyi
    - Add abstractproperty.__new__ so it can be used.
    - Add object.__new__ so it can be called.
    - Update 2.7 built-in set to be the same as PY3 set.
    - Swap max() and min() overloads so max(x, y) and min(x, y) work as expected.
    - Improve 2.7 stub for tempfile.
    - Simplify SystemRandom now it subclasses Random, for 2.7 and 3.
    - Add object.__setattr__ for 2.7.
    - Simplify PY3 len() spec, no Union with tuple needed.
    - Some updates now typing.Container is defined.
    - Add cStringIO, cPickle to six.moves. Add six.moves for PY3.