Add equality rich comparision operators to telegram objects (python-telegram-bot#604)

fixes python-telegram-bot#587

Author: jsmnbom

telegram/animation.py

@@ -48,6 +48,8 @@ def __init__(self,
         self.mime_type = mime_type
         self.file_size = file_size
 
+        self._id_attrs = (self.file_id,)
+
     @staticmethod
     def de_json(data, bot):
         """

telegram/audio.py

@@ -60,6 +60,8 @@ def __init__(self,
         self.mime_type = mime_type
         self.file_size = file_size
 
+        self._id_attrs = (self.file_id,)
+
     @staticmethod
     def de_json(data, bot):
         """