This node launches the command handler. It listens in on the topic /command
and then searches for that command in a configuration file and Popens the
command if it is found.
~config_file: Path to the config file. Default:/home/galadmin/etc/keywatch.conf
# the confi file is set up as follows
[name of section]
code = 12345
command = touch /foobar
[name of another section]
code = weather
command = curl http://wttr.in/
# and so on