Include error codes in the __str__ of exceptions.

Author: Greg Taylor

fedex/base_service.py

@@ -19,7 +19,7 @@ def __init__(self, error_code, value):
         self.error_code = error_code
         self.value = value
     def __str__(self):
-        return repr(self.value)
+        return "%s (Error code: %s)" % (repr(self.value), self.error_code)
 
 class FedexFailure(FedexBaseServiceException):
     """