Remove utils.py

The file, and contained functions, were explicitly documented as something you couldn't rely on for backwards compatibility

fbchat/__init__.py

@@ -7,11 +7,11 @@
 from __future__ import unicode_literals
 
 # These imports are far too general, but they're needed for backwards compatbility.
-from .utils import *
 from .models import *
 
 from ._graphql import graphql_queries_to_json, graphql_response_to_json, GraphQL
 from ._client import Client
+from ._util import log  # TODO: Remove this
 
 __title__ = "fbchat"
 __version__ = "1.6.5"