data tree CHANGE improve filter data tree normalization
data tree CHANGE improve filter data tree normalization

still not complete, but now it better works with duplicated leafs,
anyxml and containers.

TODO merge containment nodes selecting the same data

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