Adds two engines : Youtube with or without API

The API needs an API_KEY
The NOAPI doesn't have the published dates.

searx/engines/youtube_api.py

@@ -0,0 +1,83 @@
+# Youtube (Videos)
+#
+# @website     https://www.youtube.com/
+# @provide-api yes (https://developers.google.com/apis-explorer/#p/youtube/v3/youtube.search.list)
+#
+# @using-api   yes
+# @results     JSON
+# @stable      yes
+# @parse       url, title, content, publishedDate, thumbnail, embedded
+
+from json import loads
+from urllib import urlencode
+from dateutil import parser
+
+# engine dependent config
+categories = ['videos', 'music']
+paging = False
+language_support = True
+api_key = None
+
+# search-url
+base_url = 'https://www.googleapis.com/youtube/v3/search'
+search_url = base_url + '?part=snippet&{query}&maxResults=20&key={api_key}'
+
+embedded_url = '<iframe width="540" height="304" ' +\
+    'data-src="//www.youtube-nocookie.com/embed/{videoid}" ' +\
+    'frameborder="0" allowfullscreen></iframe>'
+
+base_youtube_url = 'https://www.youtube.com/watch?v='
+
+
+# do search-request
+def request(query, params):
+    params['url'] = search_url.format(query=urlencode({'q': query}),
+                                      api_key=api_key)
+
+    # add language tag if specified
+    if params['language'] != 'all':
+        params['url'] += '&relevanceLanguage=' + params['language'].split('_')[0]
+
+    return params
+
+
+# get response from search-request
+def response(resp):
+    results = []
+
+    search_results = loads(resp.text)
+
+    # return empty array if there are no results
+    if 'items' not in search_results:
+        return []
+
+    # parse results
+    for result in search_results['items']:
+        videoid = result['id']['videoId']
+
+        title = result['snippet']['title']
+        content = ''
+        thumbnail = ''
+
+        pubdate = result['snippet']['publishedAt']
+        publishedDate = parser.parse(pubdate)
+
+        thumbnail = result['snippet']['thumbnails']['high']['url']
+
+        content = result['snippet']['description']
+
+        url = base_youtube_url + videoid
+
+        embedded = embedded_url.format(videoid=videoid)
+
+        # append result
+        results.append({'url': url,
+                        'title': title,
+                        'content': content,
+                        'template': 'videos.html',
+                        'publishedDate': publishedDate,
+                        'embedded': embedded,
+                        'thumbnail': thumbnail})
+
+    # return results
+    return results