When parent process is killed, the child process needs to be killed as well

[sarfata]

When the parent process dies (for example because of the network error below) - the child process created stays alive and keeps hogging resources (a serial port for example).

We need to make sure that:

• The parent process does not die on network errors
• If it dies anyway, the parent process kills any child process with him

/usr/local/lib/node_modules/pi-steroid/node_modules/ddp/node_modules/ws/lib/WebSocket.js:175
    else throw new Error('not opened');
               ^
Error: not opened
    at WebSocket.send (/usr/local/lib/node_modules/pi-steroid/node_modules/ddp/node_modules/ws/lib/WebSocket.js:175:16)
    at DDPClient._send (/usr/local/lib/node_modules/pi-steroid/node_modules/ddp/lib/ddp-client.js:77:15)
    at DDPClient.call (/usr/local/lib/node_modules/pi-steroid/node_modules/ddp/lib/ddp-client.js:222:8)
    at AsteroidClient._writeConsole (/usr/local/lib/node_modules/pi-steroid/lib/asteroid_client.js:145:19)
    at null.<anonymous> (/usr/local/lib/node_modules/pi-steroid/lib/asteroid_client.js:28:10)
    at EventEmitter.emit (events.js:98:17)
    at Socket.<anonymous> (/usr/local/lib/node_modules/pi-steroid/lib/asteroid_vm.js:75:10)
    at Socket.EventEmitter.emit (events.js:95:17)
    at Socket.<anonymous> (_stream_readable.js:699:14)
    at Socket.EventEmitter.emit (events.js:92:17)
Forever detected script exited with code: 8