Support Python 3.7 (#375)

* Import collection ABC's from correct module
   They were moved into collections.abc in 3.3 and will be deprecated
   from collections in 3.8.

CHANGELOG.md

@@ -12,6 +12,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
+- Support for Python 3.7
+
 [v1.6.4][1.6.4]
 -------------------------------------------------------------------------
 ### Fixed

jwt/api_jwt.py

@@ -1,8 +1,12 @@
 import json
 import warnings
 from calendar import timegm
-from collections import Iterable, Mapping
 from datetime import datetime, timedelta
+try:
+    # Importing ABCs from collections will be removed in PY3.8
+    from collections.abc import Iterable, Mapping
+except ImportError:
+    from collections import Iterable, Mapping
 try:
     # import required by mypy to perform type checking, not used for normal execution
     from typing import Callable, Dict, List, Optional, Union # NOQA

tox.ini

@@ -15,4 +15,4 @@ commands =
 deps =
     flake8
     flake8-import-order
-    pep8-naming
+    pep8-naming