yin parser: CHANGE: review code and validity checks according to RFC 6020 sec 7.11
yin parser: CHANGE: review code and validity checks according to RFC 6020 sec 7.11

- grouping statement

PavolVican/libyang,lukasmacko/libyang,PavolVican/libyang,PavolVican/libyang,PavolVican/libyang,lukasmacko/libyang,PavolVican/libyang