add autostart entry for superkb

It might be useful that superkb autostarts.

to add an autostart-entry local:

touch $HOME/.config/autostart/superkbx.desktop
cat << EOF | tee $HOME/.config/autostart/superkbx.desktop
[Desktop Entry]
Name=superkeyboard autostart
Comment=start superkeyboard
Exec=/usr/bin/superkb -d
Terminal=false
Type=Application
Categories=System;
EOF