little refactoring

searx/engines/bing.py

 base_url = 'https://www.bing.com/'
 search_string = 'search?{query}&first={offset}'
 
+
 # do search-request
 def request(query, params):
     offset = (params['pageno'] - 1) * 10 + 1

searx/engines/bing_images.py

 base_url = 'https://www.bing.com/'
 search_string = 'images/search?{query}&count=10&first={offset}'
 
+
 # do search-request
 def request(query, params):
     offset = (params['pageno'] - 1) * 10 + 1

searx/engines/bing_news.py

 base_url = 'https://www.bing.com/'
 search_string = 'news/search?{query}&first={offset}'
 
+
 # do search-request
 def request(query, params):
     offset = (params['pageno'] - 1) * 10 + 1

searx/engines/deviantart.py

 # @using-api   no (TODO, rewrite to api)
 # @results     HTML
 # @stable      no (HTML can change)
-# @parse       url, title, thumbnail
+# @parse       url, title, thumbnail, img_src
 #
 # @todo        rewrite to api