Update ant image

config.py

             'font': {
                 'name': 'arial',
                 'size': 13
+            },
+            'background': {
+              'color': (125, 125, 125)
             }
         }
     }

socialintengine/display/pygame/visualisation.py

 from os import getcwd
 
 # TODO: Url relative au fichier
-ant = PygameImage(getcwd()+'/socialintengine/display/pygame/image/ant.png')
-bug = PygameImage(getcwd()+'/socialintengine/display/pygame/image/bug.png')
+ant = PygameImage(getcwd()+'/socialintengine/display/pygame/image/ant2.png')
+bug = PygameImage(getcwd()+'/socialintengine/display/pygame/image/ant2.png')
 rock = PygameImage(getcwd()+'/socialintengine/display/pygame/image/rock.png')
 
 visualisation = {