Oauth2client-master

**Note**: oauth2client is deprecated. No more features will be added to the
libraries and the core team is turning down support. We recommend you use
[google-auth](https://google-auth.readthedocs.io) and [oauthlib](http://oauthlib.readthedocs.io/).

* Changed OAuth2 endpoints to use oauth2.googleapis.com variants. (742)

**Note**: oauth2client is deprecated. No more features will be added to the
libraries and the core team is turning down support. We recommend you use
[google-auth](https://google-auth.readthedocs.io) and [oauthlib](http://oauthlib.readthedocs.io/).

Bug fixes:
* Fix packaging issue had erroneously installed the test package. (688)

**Note**: oauth2client is deprecated. No more features will be added to the
libraries and the core team is turning down support. We recommend you use
[google-auth](https://google-auth.readthedocs.io) and [oauthlib](http://oauthlib.readthedocs.io/).

New features:
* Allow passing prompt='consent' via the flow_from_clientsecrets. (717)

**Note**: oauth2client is now deprecated. No more features will be added to the
libraries and the core team is turning down support. We recommend you use
[google-auth](https://google-auth.readthedocs.io) and [oauthlib](http://oauthlib.readthedocs.io/).

New features:
* Allow customizing the GCE metadata service address via an env var. (704)
* Store original encoded and signed identity JWT in OAuth2Credentials. (680)
* Use jsonpickle in django contrib, if available. (676)

Bug fixes:
* Typo fixes. (668, 697)
* Remove b64 padding from PKCE values, per RFC7636. (683)
* Include LICENSE in Manifest.in. (694)
* Fix tests and CI. (705, 712, 713)
* Escape callback error code in flask_util. (710)

New features:
* New Django samples. (636)
* Add support for RFC7636 PKCE. (588)
* Release as a universal wheel. (665)

Bug fixes:
* Fix django authorization redirect by correctly checking validity of credentials. (651)
* Correct query loss when using parse_qsl to dict. (622)
* Switch django models from pickle to jsonpickle. (614)
* Support new MIDDLEWARE Django 1.10 setting. (623)
* Remove usage of os.environ.setdefault. (621)
* Handle missing storage files correctly. (576)
* Try to revoke token with POST when getting a 405. (662)

Internal changes:
* Use transport module for GCE environment check. (612)
* Remove __author__ lines and add contributors.md. (627)
* Clean up imports. (625)
* Use transport.request in tests. (607)
* Drop unittest2 dependency (610)
* Remove backslash line continuations. (608)
* Use transport helpers in system tests. (606)
* Clean up usage of HTTP mocks in tests. (605)
* Remove all uses of MagicMock. (598)
* Migrate test runner to pytest. (569)
* Merge util.py and _helpers.py. (579)
* Remove httplib2 imports from non-transport modules. (577)

Breaking changes:
* Drop Python 3.3 support. (603)
* Drop Python 2.6 support. (590)
* Remove multistore_file. (589)

* Populate `token_expiry` for GCE credentials. (473)
* Move GCE metadata interface to a separate module. (520)
* Populate `scopes` for GCE credentials. (524)
* Fix Python 3.5 compatibility. (531)
* Add `oauth2client.contrib.sqlalchemy`, a SQLAlchemy-based credential store. (527)
* Improve error when an invalid client secret is provided. (530)
* Add `oauth2client.contrib.multiprocess_storage`. This supersedes the functionality in `oauth2client.contrib.multistore_file`. (504)
* Pull httplib2 usage into a separate transport module. (559, 561)
* Refactor all django-related code into `oauth2client.contrib.django_util`. Add `DjangoORMStorage`, remove `FlowField`. (546)
* Fix application default credentials resolution order. (570)
* Add configurable timeout for GCE metadata server check. (571)
* Add warnings when using deprecated `approval_prompt='force'`. (572)
* Add deprecation warning to `oauth2client.contrib.multistore_file`. (574)
* (Hygiene) PEP8 compliance and various style fixes (537, 540, 552, 562)
* (Hygiene) Remove duplicated exception classes in `oauth2client.contrib.appengine`. (533)

NOTE: The next major release of oauth2client (v4.0.0) will remove the `oauth2client.contrib.multistore_file` module.