Filter out special characters displayed by avahi-browse

[tempuser]

avahi-set-host-name allows an user to embed terminal control characters in the host name, which are blindly output by avahi-browse, causing a remote user's terminal to interpret the control chars.

For example, setting the hostname like this:

$ avahi-set-host-name echo -e '\007\033#8_bip_me'

will create a host name that contains a BEL control char and and escape sequence which fills the screen with 'E' (on supported terminals).

Somebody running avahi-browse on another computer will get something like:

$ avahi-browse -a + eth0 IPv4 EEEE....(lots of E's)EEEEEEEEEEEE_bip_me [00:xx:xx:xx:xx:xx] Workstation

[lennart]

Fixed now in git.