* [SC] Overall cleanup.
* [FIX] at_halt/1 must not be asserted.
* [GRAPH_WEB,VERTEX_COORDINATE,NEW] Rewrite to DCGs.
* [PROLOG_PACKAGE,NEW] New module for loading Prolog packages easily.
* [XML_DOM,SC] Relocated xml_dom_as_atom//1, now used in all places.