Subscribe to event instead of polling

[figarocorso]

I came to this repo after a quick googling, so probably many others my come here too. I cleaned the code a little bit and then realised we were constantly polling, which seemed not OK.

I googled for an alternative, copy-pasted here and there, removed code and finally got something working for me. Pointing here to the code figarocorso#1 before opening a PR because it changes the script from top to bottom.