This is an ugly hack AND IT DOESN'T WORK ON 5.0 AND UP
It's just a proof of concept code for barcamp talk I gave with @pjakubczyk at droidcon Berlin 2015
Go and see the presentation http://www.slideshare.net/pelotasplus/how-to-recognise-that-the-user-has-just-uninstalled-your-app-droidconde-2015