Add Sauce Labs configuration keys to strArgs

Right now you can't do something as follows because Sauce Labs configuration
options are not passed to protractor:

    options: {
      keepAlive: false,
      args: {
        sauceUser: 'myuser',
        sauceKey: 'mykey',
        baseUrl: 'http://www.google.com',
        params: { ... }
      }
    }