Make the routing of functions more systematic
Make the routing of functions more systematic

Now there are 4 kinds of object, PATH, FILE, LIST and OTHER.  Each kind is converted to/from the virtual filesytem representation, using specific functions.  The router takes a list of types for the arguments, and for the return type, and calls the appropriate conversion functions before/after calling the routed function

jupyter/jupyter-drive,Carreau/jupyter-drive,jupyter/jupyter-drive,jupyter/jupyter-drive,Carreau/jupyter-drive