copyTo abstract method
Copy this resource to a child of the parentFolder
with the same kind and
shortName as this resource. If this resource is a folder, then all of
the contents of the folder will be recursively copied.
The parent folder is created if it does not already exist.
Existing files and folders will be overwritten.
Return the resource corresponding to this resource in the parent folder.
Implementation
Resource copyTo(Folder parentFolder);