Many improvements to DCG tools for the purpose of writing the grammar of Turtle 1.1 and SPARQL 1.1 Query and Update.

* [DCG_CARDINAL,NEW] Added decimal_fraction//1.
* [DCG_CARDINAL,NEW] Added 'integer?'//1.
* [DCG_CARDINAL,SC] Removed the unused expomemt_sign//1, sign//2.
* [DCG_CARDINAL,NEW] Added 'sign?'//1.
* [DCG_CARDINAL,SC] Removed unused signed_number//1, unsigned_number//[1,3].
* [DCG_CONTENT,NEW] Added quoted//2, allowig the typo of quotes to be specified.
* [DCG_CONTENT,NEW] Added triple_quote//1, allowing triple quotes the be parsed/generated.
* [DCG_META,NEW] Added dcg_atom_codes//2, connecting the word level (atoms) to the character level (lists of codes).
* [FLOAT_EXT,DOC] Added example to documentation of float_parts/3.
* [SPARQL,TURTLE,NEW] Working on complete (re)write of the grammar for Turtle 1.1 and SPARQL 1.1 Query and Update, intented to reuse each other.
* [TYPECHECK,NEW] Added negative/postive float/integer check predicates.
* [XML_CHAR,NEW] XML character definitions in one module. Coming from XML_DATATYPE.
* [XML_WORD,NEW] XML word definitions in one module. Coming from XML_DATATYPE.