initialize random_event action on Arena

entities/arena.py

@@ -103,7 +103,8 @@ class BrSimArena():
 
   def do_random_event(self):
     #XXX random player does random action according to his inventory health, wounds, available weapons on the world, etc...
-    pass
+    self.eventClass.resolve_event()
+    self.next_day()
 
   def supporter_donation(self):
     #XXX supporter donate a random item or weapon to a random player