title: Scrapy selector not working on Splash response
body: <p>I'm trying to scrape some dynamic content using Scrapy.
  I have succesfully set up Splash to work along with it.
  However, the selectors of the following spider yield empty results:</p>
  
  <pre><code># -*- coding: utf-8 -*- 
  
  import scrapy
  from scrapy.selector import Selector
  from scrapy_splash import SplashRequest
  
  class CartierSpider(scrapy.Spider):
    name = 'cartier'
    start_urls = ['http://www.cartier.co.uk/en-gb/collections/watches/mens-watches/ballon-bleu-de-cartier/w69017z4-ballon-bleu-de-cartier-watch.html']
  
    def start_requests(self):
      for url in self.start_urls:
        yield SplashRequest(url, self.parse, args={'wait': 0.5})
  
    def parse(self, response):
      yield {
        'title': response.xpath('//title').extract(),
        'link': response.url,
        'productID': Selector(text=response.body).xpath('//span[@itemprop="productID"]/text()').extract(),
        'model': Selector(text=response.body).xpath('//span[@itemprop="model"]/text()').extract(),
        'price': Selector(text=response.body).css('div.price-wrapper').xpath('.//span[@itemprop="price"]/text()').extract(),
      }
  </code></pre>
  
  <p>The selectors work just fine using the Scrapy shell, so I'm very confused about what is not working.</p>
  
  <p>The only difference I can find among the two situations is that the encoding of the string <code>response.body</code> is treated differently: it's just gibberish if I try to print/decode it from within the <code>parse</code> function.</p>
  
  <p>Any hint or reference would be greatly appreciated.</p>