Added a merchant class and a talk_to method to interact with friendly entities

squirrelbattle/interfaces.py

@@ -435,4 +435,7 @@ class FriendlyEntity(Entity):
         super().__init__(*args, **kwargs)
         self.maxhealth = maxhealth
         self.health = maxhealth if health is None else health
+
+    def talk_to(self, player : Player) -> None:
+        #TODO