#57 Replace ultrabayd unsafe echo of BEL character with printf

[Clarence Risher]

The contrib/ultrabayd script uses echo -n "\07" > /dev/tty1 to beep the system speaker. Using echo with backslash control characters is not safe across different shells. This patch replaces that echo with an invocation of printf instead.

See https://wiki.ubuntu.com/DashAsBinSh#echo