and process properties in that order. This establishes iteration
order on object properties, making the object_properties() method
unnecessary. So the latter method has been deleted. All uses
of that method have been removed.
Removed unnecessary deepcopy() in STIXJSONEncoder, to improve
efficiency. This uncovered a bug which had been affecting
STIXdatetime instances. Not deepcopying doesn't trip the bug,
which can change serialization format. This caused a unit
test to fail, which was checking serialization format. I fixed
the unit test.
Fixed a bug in _STIXBase.__repr__ which caused it to omit all
properties with falsey values. This caused several unit tests
to break, since they were written against the old buggy repr
format. Notably, 'revoked=False' was never included in reprs
before, but it is now.