.move(...) can now move into any folder

Ok, so it works. 

But I'm not at ease with the API. And not only because target can be an int or not, but in general, when I send a "file reference" to the API, there is no standard way to do it.

Sometime, I send just a *handle* ( like ``'t8G12Vj9'`` )
Sometime, I send *file structure* ( like ``{'h': 't8G12Vj9', ...}`` )
Sometime, I send *find result structure* ( like ``('t8G12Vj9', {'h': 't8G12Vj9', ...})`` )

When I'm adding new code to the API, I try to be coherent with the existing calls, but they aren't coherent in the first place.