Add command line argument to support serving files from a specific directory

[indera]

[cmsethi]

hi, I tried...

parser.add_argument(
       '-r', '--root', dest='root', default=StubSFTPServer.ROOT,
       help='Directory to serve as root for the server'
   )

but it failed. Can someone help me to set a specific directory rather than the cwd directory. thanks and regards.