[mod] move wolframalpha to "science" category

searx/settings.yml

     engine : wolframalpha_noapi
     timeout: 6.0
     disabled : True
+    categories : science
 
 #The blekko technology and team have joined IBM Watson! -> https://blekko.com/
 #  - name : blekko images

searx/webapp.py

                    gettext('videos'),
                    gettext('it'),
                    gettext('news'),
-                   gettext('map'))
+                   gettext('map'),
+                   gettext('scence'))
 
 outgoing_proxies = settings['outgoing'].get('proxies', None)