Mostly plDoc updates.

* [DOC,SC] Use Markdown section indicators and code segment indicators everywhere.
* [KMC_1200,SC] Merged the Picarta and Redactiebladen parse for this KMC into one DCG rule.
* [STCN,SC] The project mnemonic is now also called stcn (indicating the path of the codebase).
* [STCN_WEB,SC] Updated this module to fit the new architecture.
Merge
* [STCN_WEB,FIX] Rewrote the extraction of PPNs from the URI to use proper dereferencing.
Many fixes to the KMCs. Now parsing the entire redactiebladen. Some problemantic cases need to be handled...

* [KMC_0500,FIX] 'Aax' would not parse due to parse/2. Now using parse/3.
* [KMC_0500,FIX] Chars/codes got mixed up.
* [KMC_1500,FIX] The language predicates need rdf_equal/2.
* [KMC_1700,FIX] The country predicates need rdf_equal/2.
* [KMC_30XX,FIX] dcg_until/2 behavior was changed, using dcg_without/2 instread.
* [KMC_4043,FIX] dcg_until/2 behavior was changed, using dcg_without/2 instread.
* [KMC_4062,FIX] dcg_word/1 replaced with dcg_word_atom/1 and rewrote the matching of the format atom to the corresponding format resource.
* [REDACTIEBLADEN,FIX] Made one small alteration to ease the parsing process.
* [STCN,SC] Rewrote the entire STCN script. Now includes vocabulary, redactiebladen, Picarta, and cleaning. All in one predicate.
* [STCN_KMC,O] Relocated kmc_code/3 for a slight speed improvement.