Merge pull request #122 from pointhi/bugfix

[fix] #121, HTTP 500 Error if res["content"] == None

searx/search.py

         weight = 1.0
 
         # strip multiple spaces and cariage returns from content
-        if 'content' in res:
+        if res.get('content'):
             res['content'] = re.sub(' +', ' ',
                                     res['content'].strip().replace('\n', ''))