pull saved position into HParserCacheValue and fix segfault in grow()
more leftrec fixes: head caching and input rewinding
rename leftrec_nonempty test to leftrec-ne
disable test /core/parser/packrat/leftrec
enable leftrec-ne test for LALR and GLR backends
Merge pull request #93 from pesco/fix-left-recursion

Fix left-recursion with packrat