GTree support
I'm getting warnings when returning GTree:
Unknown container Type(target_giname=GLib.Tree, ctype=GTree*) for element-type annotation
When GTree is quite clearly a container type (and a key=>value one at that) and g-i should probably recognise it as such
return value: Invalid non-constant return of bare structure or union; register as boxed type or (skip)
No idea what this is about