App restart when a device locks its screen

[ptc-mklaudiny]

NodeMobile looses ability to listen its connections when the screen is locked. It emits an exception which is unhandled and this makes Node to shutdown. In turn, this calls exit() on parent process (swift app itself). The app crashes because the shutdown is not coordinated with Engine and while the Engine is being destroyed there is bad memory access abort.
Interestingly the app somewhat restarts itself after this ...

[ptc-mklaudiny]

An attempt to handle the exceptions from NodeMobile gracefully has not been successful for far.
#976