afkcron simply reports the idle time of the X11 server to a shell script.
Originally, it was reading config files and also handling the return of the
user by decreasing priority of launched processes or killing them etc.
Now I considered it's best for it to be rather stupid and delegate this
to a shell script for example.
afkcron [path to script] [how often idle time should be polled, in seconds]
Example: afkcron script.sh 30
First argument: "active" (if idle time has stopped), "idle": When idling
Second argument: the number of seconds X11 is idling.
libX11, libXss. Should be a given.