Flask-jwt-extended

In this release, we are no longer toggling the flask `PROPAGATE_EXCEPTIONS = True` setting in this extension. It was set in here initially to get things working with `flask-restful`, but setting a global flask option in here just so that it would work with another flask extension was a poor design choice.

Note that if you are using flask-restful (or possibly other extensions) and the error handlers stop working after this update, you will need to manually set the `PROPAGATE_EXCEPTIONS` setting in your configuration to keep everything working. Sorry all the inconvenience.

* Removed `PROPAGATE_EXCEPTIONS` setting from this extension
* Internal cleanup and refactoring

* `jwt_required` (et al) no longer require authorization to be present on an `OPTIONS` request (119)
* Add `Add Werkzeug>=0.14` to install requirements (115)

* Adds ability to use the `samesite` cookie attribute (34, 113, 115). Requires Werkzeug >= 0.14. Thanks farshiana!

* Exports `get_csrf_token` to the api (112)

* Add ability to set the `fresh` argument when creating access tokens to a `datetime.timedelta`, which will cause the token to be marked as fresh from now until the timedelta is past (107). Thanks dunkmann00!

* Add ability to disable expires check for JWTs (105 and 106). Thanks beenje!