ZeroNet-Kivy keeps crashing. Bring back background processing.

Both 32-bit and 64-bit versions crash every so often. I'm not sure why. It's not me killing the process.

Could you also bring back the background processing so the window being closed doesn't kill the process? This is unrelated but I think it's essential. Also provide an auto-start option so users don't have to remember to start ZeroNet themselves. Make background processing optional so the new foreground processing remains an option for panic button functionality.