Django-push-notifications

* BACKWARDS-INCOMPATIBLE: Drop support for Django Rest Framework < 3.7
* BACKWARDS-INCOMPATIBLE: NotificationError is now moved from `__init__.py` to `exceptions.py`
* Import with `from push_notifications.exceptions import NotificationError`
* PYTHON: Add support for Python 3.7
* APNS: Drop apns_errors, use exception class name instead
* FCM: Add FCM channels support for custom notification sound on Android Oreo
* BUGFIX: Fix error when send a message and the device is not active
* BUGFIX: Fix error when APN bulk messages sent with localized keys and badge function
* BUGFIX: Fix `Push failed: 403 fobidden` error when sending message to Chrome WebPushDevice

* Pin dependency to apns to <0.6.0 to fix a Python version
incompatibility.
* Add configuration for semi-automatic releases via Jazzband.

* BACKWARDS-INCOMPATIBLE: Drop support for Django < 1.11
* DJANGO: Support Django 2.0
* NEW FEATURE: Add support for WebPush

* BACKWARDS-INCOMPATIBLE: Remove `push_notifications.api.tastypie` module. Only DRF is supported now.
* BACKWARDS-INCOMPATIBLE: Drop support for Django < 1.10
* BACKWARDS-INCOMPATIBLE: Drop support for Django Rest Framework < 3.5
* DJANGO: Support Django 1.10, 1.11
* APNS: APNS is now supported using PyAPNS2 instead of an internal implementation.
* APNS: Stricter certificate validity checks
* APNS: Allow overriding the certfile from send_message()
* APNS: Add human-readable error messages
* APNS: Support thread-id in payload
* FCM: Add support for FCM (Firebase Cloud Messaging)
* FCM: Introduce `use_fcm_notification` option to enforce legacy GCM payload
* GCM: Add GCM_ERROR_TIMEOUT setting
* GCM: Fix support for sending GCM messages to topic subscribers
* WNS: Add support for WNS (Windows Notification Service)
* MISC: Make get_expired_tokens available in push_notifications.utils

* APNS: Increased max device token size to 100 bytes (WWDC 2015, iOS 9)
* BUGFIX: Fix an index error in the admin

* BACKWARDS-INCOMPATIBLE: Drop support for Python<3.4
* DJANGO: Support Django 1.9
* GCM: Handle canonical IDs
* GCM: Allow full range of GCMDevice.device_id values
* GCM: Do not allow duplicate registration_ids
* DRF: Work around empty boolean defaults issue (django-rest-framework1101)
* BUGFIX: Do not throw GCMError in bulk messages from the admin
* BUGFIX: Avoid generating an extra migration on Python 3
* BUGFIX: Only send in bulk to active devices
* BUGFIX: Display models correctly in the admin on both Python 2 and 3