Add an option to disable system notifications about compilations

[Diakon5]

Could be my OCD talking, but when I relaunch the kivy reloader, I don't like the fact it spits out system notifications. It's not a major problem once the project is more estabilished, to the point where relaunching doesn't happen, but it's just... Mildly annoying. Should be easy to make optional, will try a PR