Re-starts the XRPi program immediately and ungracefully.
It is typically used by remote sysops to restart the program
after modifying the config files, or installing a new version
of the software.
All open links are closed, and the program starts again from
scratch.
WARNING: If you replace the "xrpi" file while the program is running, you MUST remember to chmod the new file to make it executable before using the RESTART command. Otherwise you will "bork" your Pi. Where possible, it is safer to exit XRPi and start it afresh.