Fix the lack of line number as reported by Johan Corveleyn <jcorvel@gmail.com>

* parser.c include/libxml/parser.h: add an XML_PARSE_BIG_LINES parser
  option not switch on by default, it's an opt-in
* SAX2.c: if XML_PARSE_BIG_LINES is set store the long line numbers
  in the psvi field of text nodes
* tree.c: expand xmlGetLineNo to extract those informations, also
  make sure we can't fail on recursive behaviour
* error.c: in __xmlRaiseError, if a node is provided, call
  xmlGetLineNo() if we can't get a valid line number.
* xmllint.c: switch on XML_PARSE_BIG_LINES in xmllint