Fix error in mapping RDFa version compatibility for Sesame

The mapping code for Sesame to enable users to select RDFa-1.0 parsing was broken due to a typo. This pull request fixes that, and also uses Rio.write in some tests.

The issue with Any23 and unexpanded CURIEs was due to invalid RDFa files (not including a space in the prefix declarations), so that code did not require any changes here so far.