Initial implementation of Std:Generator.
Initial implementation of Std:Generator.

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