Include name of object that failed in exceptions.  Perhaps also
include more information about the failure like was in the previous
version, e.g., "ERROR: rename: \"$object\" to \"$name\" in
\"$folder\": $@".  May have to implement it by setting an instance
variable that contains the name of the current object being operated
on and a description of the operation being attempted so that this
information can be accessed from anywhere when an exception is to be
thrown.  Maybe implement all this in the Exceptions object.

Add methods to query usage/quota and to edit permissions.

Write a program called ycp, modeled after scp: similar options and
file specification format ("user@yahoo:/folder/file").
