Fix automated tests (add check_process_delay to Nightwatch config)

See: https://github.com/nightwatchjs/nightwatch/issues/2138

 .travis.yml

@@ -16,5 +16,5 @@
  - 'npm install nightwatch selenium-server chromedriver geckodriver'

script:
# - 'node_modules/.bin/nightwatch -e chrome-headless'
  - 'node_modules/.bin/nightwatch -e chrome-headless'
  - 'node_modules/.bin/nightwatch -e firefox-headless'

 nightwatch.conf.js

@@ -12,6 +12,7 @@
      'webdriver.chrome.driver': chromedriver.path,
      'webdriver.gecko.driver': geckodriver.path,
    },
    check_process_delay: 1000,
  },
  test_settings: {
    'chrome': {