add /etc-based hook handler for joystick events

[zacchiro]

I've written this UNIX-like event handler / hook runner for joystick events for my own needs, but I guess it might be useful to others.

It allows to react to joystick events by simply dropping executable scripts under specific /etc/joystick.d/ subdirectories. The hook scripts can be in any language and even just symlinks to other executables available on the system. I believe this might lower the barrier for using the joystick, as one not even needs to write in Python to simply plug the joystick into existing system executables.

Note that there is a dependency on run-parts (8), which is specific to Debian and its derivatives. The dependency is satisfied on Raspbian, but might not be on non-Debian based RPi distros.

[rzr]

may the joystick-handler script named to have .py suffix?
then it can be installed and optionally symlinked to ../bin/ joystick-handler ?