* [FILE_MIME,SC] Added mime_dir/3, coming from SEMURI_AP, to beused in AP_STAGE.
* [RDF_META,SC] Removed several unused predicates.
* [RDF_SERIAL,SC] Added RDF conversion predicates, coming form the now defunct module RDF_SERIAL_CONV.
* [SC] Removed nodebug statements.
* [URI_EXT,NEW] Added download_to_directory/3, to be used in AP_STAGE.