Removes unused code

pydtn/routers/base.py

-from collections import namedtuple
-
 class Router:
     '''
     Base Router class

pydtn/routers/community.py

-from pydtn.communities import LouvainCommunity
-
 from .base import Router
 
 class CommunityRouter(Router):
@@ -20,7 +18,8 @@ class CommunityRouter(Router):
         community = self.node.community
         return [met for met in links if met not in community]
 
-    def best(self, nodes, key):
+    @staticmethod
+    def best(nodes, key):
         best = max(nodes, key=key)
         return best, key(best)