json_encode cleanups
json_encode cleanups

- few optimizations

peachpiecompiler/peachpie,iolevel/peachpie-concept,iolevel/peachpie-concept,peachpiecompiler/peachpie,peachpiecompiler/peachpie,iolevel/peachpie,iolevel/peachpie-concept,iolevel/peachpie,iolevel/peachpie