Additions to vsys

Library functions for vsys

I've added some Library functions that can be used to build vsys scripts. Hopefully, they should reduce all the scripts that we'd ever want to write, or at least the services supported by proper, to a few lines of code.

The library:

- connect_fd        [ connects an fd in a slice to an fd on the node]

( implements open_file)

 - mount_dir         [ bind-mounts a directory into a slice ]

 - socket_filter      [ basically a wrapper for the UNIX 'socket' program which restricts you to a fixed set of hosts and/or ports]