* [RFC2396,SC] Rewrote the test predicates using plunit.
* [RFC5646,SC] Made langtag// greedy-first to avoid unneccessary backtracking.
* [RFC5646,FIX] Added hyphens in front of extensions.
* [RFC5646,FIX] Added all hyphens to the parse tree.
* [RFC5646,FIX] Scripts consist of letters, not decimal digits.
* [RFC5646,DEB] Added unit tests for parsing.
Added ABNF grammar rules.
Next we want to:
  1. Finish record-jar support.
  2. Create RDF DB based on record-jar text file (IANA language subtag registry).
  3. Add validity checks to language tag module.
  4. Rewrite already implemented RFC modules to be as close to their standard specification as possible (using the new tools in modules DCG_GENERIC and ABNF).

* [ABNF,NEW] New module implementing the grammatical rules described by the ABNF RFC standard (mostly renaming of functionality that was already in DCG_ASCII and DCG_CARDINAL).
* [DCG_CONTENT,NEW] Added spaces//0.
* [DCG_GENERIC,NEW] Added dcg_multi//1 wrapper around dcg_multi//2.
* [DCG_GENERIC,NEW] Added dcg_multi//4 for DCG rules with two arguments.
% [DCG_GENERIC,SC] Extended and simplified API for DCG peeking: (A) Removed dcg_peek_atom//1 and dcg_peek_char//1. (B) The argument for dcg_peek//1 is now a DCG rules (was a code).
* [LIST_EXT,NEW] Added append_intersperse/3.
* [RECORD_JAR,NEW] Started implementing the record-jar format for storing records in text files.
* [RFC2396,SC] DCG and unit tests in separate modules.
* [RFC5646,SC] DCG and IANA registry access in separate modules.
* [RFC5646,EXT] Completed the implementation of the IANA registry parser. Too slow for actual use. We are working on a DB for this.