add year to time range to engines which support "Last year"

Engines:
 * Bing images
 * Flickr (noapi)
 * Google
 * Google Images
 * Google News

searx/engines/bing_images.py

 thumb_url = "https://www.bing.com/th?id={ihk}"
 time_range_dict = {'day': '1440',
                    'week': '10080',
-                   'month': '43200'}
+                   'month': '43200',
+                   'year': '525600'}
 
 # safesearch definitions
 safesearch_types = {2: 'STRICT',

searx/engines/flickr_noapi.py

 time_range_support = True
 time_range_dict = {'day': 60 * 60 * 24,
                    'week': 60 * 60 * 24 * 7,
-                   'month': 60 * 60 * 24 * 7 * 4}
+                   'month': 60 * 60 * 24 * 7 * 4,
+                   'year': 60 * 60 * 24 * 7 * 52}
 
 
 def build_flickr_url(user_id, photo_id):

searx/engines/google.py

 time_range_search = "&tbs=qdr:{range}"
 time_range_dict = {'day': 'd',
                    'week': 'w',
-                   'month': 'm'}
+                   'month': 'm',
+                   'year': 'y'}
 
 # other URLs
 map_hostname_start = 'maps.google.'

searx/engines/google_images.py

  @parse       url, title, img_src
 """
 
+from datetime import date, timedelta
 from urllib import urlencode
 from json import loads
 from lxml import html
 
+
 # engine dependent config
 categories = ['images']
 paging = True
     '&yv=2'\
     '&{search_options}'
 time_range_attr = "qdr:{range}"
+time_range_custom_attr = "cdr:1,cd_min:{start},cd_max{end}"
 time_range_dict = {'day': 'd',
                    'week': 'w',
                    'month': 'm'}
 
 # do search-request
 def request(query, params):
-
     search_options = {
         'ijn': params['pageno'] - 1,
         'start': (params['pageno'] - 1) * number_of_results
 
     if params['time_range'] in time_range_dict:
         search_options['tbs'] = time_range_attr.format(range=time_range_dict[params['time_range']])
+    elif params['time_range'] == 'year':
+        now = date.today()
+        then = now - timedelta(days=365)
+        start = then.strftime('%m/%d/%Y')
+        end = now.strftime('%m/%d/%Y')
+        search_options['tbs'] = time_range_custom_attr.format(start=start, end=end)
 
     if safesearch and params['safesearch']:
         search_options['safe'] = 'on'

searx/engines/google_news.py

 time_range_attr = "qdr:{range}"
 time_range_dict = {'day': 'd',
                    'week': 'w',
-                   'month': 'm'}
+                   'month': 'm',
+                   'year': 'y'}
 
 
 # do search-request

tests/unit/engines/test_youtube_noapi.py

         self.assertIn(query, params['url'])
         self.assertIn('youtube.com', params['url'])
 
+    def test_time_range_search(self):
+        dicto = defaultdict(dict)
+        query = 'test_query'
+        dicto['time_range'] = 'year'
+        params = youtube_noapi.request(query, dicto)
+        self.assertIn('&sp=EgIIBQ%253D%253D', params['url'])
+
+        dicto['time_range'] = 'month'
+        params = youtube_noapi.request(query, dicto)
+        self.assertIn('&sp=EgIIBA%253D%253D', params['url'])
+
+        dicto['time_range'] = 'week'
+        params = youtube_noapi.request(query, dicto)
+        self.assertIn('&sp=EgIIAw%253D%253D', params['url'])
+
+        dicto['time_range'] = 'day'
+        params = youtube_noapi.request(query, dicto)
+        self.assertIn('&sp=EgIIAg%253D%253D', params['url'])
+
     def test_response(self):
         self.assertRaises(AttributeError, youtube_noapi.response, None)
         self.assertRaises(AttributeError, youtube_noapi.response, [])