Fixes for RDF tabular.

* [DCG_META,FIX] Strip module.
* [DCG_META,FIX] Index correction not necessary.
* [RDF_STAT,FIX] Counting datatype literals did not work for datatype IRI `rdf:langString`.
* [RDF_TABULAR_CLASS,FIX] Term in table caption is codes list.
* [RDF_TABULAR_DATATYPE,FIX] Missing table header cells.
* [RDF_TABULAR_DATATYPE,FIX] Missing table header.
* [RDF_TABULAR_TERM,SC] Markup.
* [RDF_TERM_HTML,FIX] Argument order.