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Released on 15 June 2013.
Fixed several bugs in milestones(), and made logging more verbose. Converters
can be compared for equality now. Converter.steps_cached now officially
indicates whether a temporary step value is active. Added method
Converter.end_temporary_steps() to unconditionally reset a temporary step value.
Converter.revert() no longer uses the Container.deliver() method to return items
in order for them not being counted as delivered. Converter.draw() no longer
checks how many units have been delivered, but how many would be delivered in
the next step, and will refuse to draw when this would exceed
Converter.max_units. Simulation.save_dot() now groups equivalent converters to a
single graph node. Updated doctests in README.