code: function spawnObservable(command, args) {
    return Observable.create(observer => {
      const cmd = spawn(command, args);
      observer.next(''); // hack to kick things off, not every command will have a stdout
      cmd.stdout.on('data', (data) => { observer.next(data.toString('utf8')); });
      cmd.stderr.on('data', (data) => { observer.error(data.toString('utf8')); });
      cmd.on('close', (data) => { observer.complete(); });
    });
  }
docs: Create an Observable of a spawned child process.
  @param {string} command
  @param {string[]} args