Get rid of spawning shell windows if nodemon is started without console.

If nodemon is started without it's own console (example: via pm2) on Windows, it spawns console windows for it's monitored processes. This should get rid of this behaviour.

lib/spawn.js

@@ -44,6 +44,7 @@ module.exports = function spawnCommand(command, config, eventArgs) {
     sh = process.env.comspec || 'cmd';
     shFlag = '/d /s /c';
     spawnOptions.windowsVerbatimArguments = true;
+    spawnOptions.windowsHide = true;
   }
 
   const args = command.join(' ');