Repairing feature lapse in XML/JSON conversions

[wendellpiez]

Committer Notes

Testing exposed a bug in the XML/JSON conversions (both ways, minor but fatal bugs). This commit repairs the known bugs with the present versions of OSCAL metaschemas.

Addresses usnistgov/OSCAL#596 and with luck, removes a blocker to integration.

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Changes to Core Features:

Delivers functionality not demonstrated in earlier samples.

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