* xmlschemas.c: Fixed a potential memory leak in
  xmlSchemaCheckCSelectorXPath() when an internal error occurs.
  Fixed setting of ctxt->err to the given error code in
  the parsing error functions.
* pattern.c: Added internal xmlCompileIDCXPathPath() as a
  starting point for IDC XPath compilation; this and some other
  tiny changes fixes issues regarding whitespace in the
  expressions and IDC selector/field relevant restrictions of
  the subset of XPath. Fixed a missing blocking of attributes
  in xmlStreamPushInternal().