The filters map between a common subset of Word smart tags and Writer
RDF annotations, and when doing so, they need to know what path to use
for a smart tag namespace and also the other way around: what RDF types
are interesting for smart tag purposes.

It turns out there is BAILS specification at
<http://www.tscp.org/wp-content/uploads/2013/08/TSCP_BAILSv1.pdf> that
describes how to refer to BAF objects, so use that instead of our custom
RDF statement / document metadata key names.

Change-Id: Iac569608b05aa61547f664f2a5df7d46fe46da76