* [RDF_REIFICATION,NEW] Added method for printing statements.
* [XML_DOM,FIX] Module HTML is needed for DTD path.
Updates to label writing.

* [GV_DCG,EXT] Added simple version of HTML labels.
* [HTML,NEW] Added shortcut predicates html_entity/[1,2] for creating simple HTML tags in a DCG.
* [PRINT_EXT,EXT] Added the `brackets` option for print_tuple/3 and print_tuple/2. Also added documentation and use two parameters for the pair input.
* [RDF_NAME,SC] Added options argument to rdf_pair_name/3 and extra parameter for second pair member.
* [RDF_NAME,SC] Cleanup of public predicates list.