* pattern.c, xpath.c, include/libxml/pattern.h: Further
enhancement for XPath streaming, consolidated with
schemas usage of pattern.c. Added a new enum
xmlPatternFlags.
* doc/*, testapi.c, elfgcchack.h: updated to reflect new
enum.
* test/XPath/tests/mixedpat, test/XPath/docs/mixed,
result/XPath/mixedpat: added regression test for problems
reported in bug306348
