* [DCG_CONTENT,EXT] Use proper meta-arguments for quoted//2 and triple_quote//1.
* [RADIX,NEW] Added dec_hex/2, dec_to_hex/2, and hex_to_dec/2.
* [SPARQL_CHAR,NEW] Completed 'PERCENT'//1, 'PLX'//1.
* [SPARQL_LITERAL,NEW] Added the four literal variants.
* [SPARQL_WORD,NEW] Completed SPARQL terminals.