Implement automatic namespace discovery and prefix generation in TURF serializer.
Description
The TURF serializer currently requires that all namespaces be defined, or the full form will be used. Now that we have vocabulary registration facilities from (used in for example), we can have the TURF parser generate namespace prefixes as needed.
The TURF serializer currently requires that all namespaces be defined, or the full form will be used. Now that we have vocabulary registration facilities from (used in for example), we can have the TURF parser generate namespace prefixes as needed.