------------------
Deprecated
''''''''''
- support for unresolved output variables in ``session.evaluate``, use ``sessions.solve`` for that purpose
- support for arguments of type Variable in ``Op.__call__``, use ``Op.op`` instead
Changed
'''''''
- simplify ``op`` decorator
- simplify default implementation of ``Op.__repr__``
- complete rewrite of the readme
Added
'''''
- method ``Op.op`` to be used in place of direct invocation of an Op instance when building a graph
- the ``Variable`` class, the ``op`` decorator and the functions ``evaluate``, ``apply``, ``solve`` and ``solve_requirements`` are now exposed at package
level.