Creates a symbolic file link to a GenericDataFile at/from a given
  destination pathname.
# S3 method for GenericDataFile
linkTo(this, filename=getFilename(this), path=NULL, skip=!overwrite, overwrite=FALSE,
  ...)Returns a GenericDataFile (of the same class as the source file)
  referring to the file via the link.
The filename and the path for the link. The default is to use the same filename as the source file.
If TRUE and a file with the same name as argument
    link already exists, then the nothing is done.
If TRUE, an existing link file is overwritten,
    otherwise not.
Additional arguments passed to createLink.
In order for this method to succeed on Windows,
  the client/R session must run with sufficient privileges.
  See createLink for more details.
Henrik Bengtsson
To copy a GenericDataFile, see *copyTo().
  Internally createLink is used.
  For more information see GenericDataFile.