(though LIBO_INTERNAL_ONLY, as it needs C++11, so cannot in general be used in
URE client code; I think it's better to not offer it outside LO at all, than
based on a feature-check macro, and thus catch accidental misuses of it via
CppunitTest_odk_checkapi)

...plus adapting binaryurp/ to use the new feature

Change-Id: I9a88a0e9eac5daf72896470e8b6a1deb1a6fc88f