upnp: Add filter by type in browse() operation
upnp: Add filter by type in browse() operation

UPnP/DLNA protocol does not allow to apply filters in the browse operation.

So the way to implement it is to rely on the search() operation: browsing in
container "foo" is like searching all the elements with @parentID=\"foo\". And
thus we can apply here the filter by type (allowing also containers).

This means that filter by type is only available in case the source supports
search() operation.

kyoushuu/grilo-plugins,grilofw/grilo-plugins,kyoushuu/grilo-plugins,vrutkovs/grilo-plugins,jasuarez/grilo-plugins,MikePetullo/grilo-plugins,MathieuDuponchelle/grilo-plugins,MathieuDuponchelle/grilo-plugins,GNOME/grilo-plugins,MathieuDuponchelle/grilo-plugins,vrutkovs/grilo-plugins,grilofw/grilo-plugins,vrutkovs/grilo-plugins,MathieuDuponchelle/grilo-plugins,GNOME/grilo-plugins,MikePetullo/grilo-plugins,vrutkovs/grilo-plugins,kyoushuu/grilo-plugins,MikePetullo/grilo-plugins,jasuarez/grilo-plugins