Flask 0.11 发布了，求英文好的解说下主要新特性

Version 0.11
------------

Released on May 29th 2016, codename Absinthe.

- Added support to serializing top-level arrays to :func:`flask.jsonify`. This
introduces a security risk in ancient browsers. See
:ref:`json-security` for details.
- Added before_render_template signal.
- Added `**kwargs` to :meth:`flask.Test.test_client` to support passing
additional keyword arguments to the constructor of
:attr:`flask.Flask.test_client_class`.
- Added ``SESSION_REFRESH_EACH_REQUEST`` config key that controls the
set-cookie behavior. If set to ``True`` a permanent session will be
refreshed each request and get their lifetime extended, if set to
``False`` it will only be modified if the session actually modifies.
Non permanent sessions are not affected by this and will always
expire if the browser window closes.
- Made Flask support custom JSON mimetypes for incoming data.
- Added support for returning tuples in the form ``(response, headers)``
from a view function.
- Added :meth:`flask.Config.from_json`.
- Added :attr:`flask.Flask.config_class`.
- Added :meth:`flask.config.Config.get_namespace`.
- Templates are no longer automatically reloaded outside of debug mode. This
can be configured with the new ``TEMPLATES_AUTO_RELOAD`` config key.
- Added a workaround for a limitation in Python 3.3's namespace loader.
- Added support for explicit root paths when using Python 3.3's namespace
packages.
- Added :command:`flask` and the ``flask.cli`` module to start the local
debug server through the click CLI system. This is recommended over the old
``flask.run()`` method as it works faster and more reliable due to a
different design and also replaces ``Flask-Script``.
- Error handlers that match specific classes are now checked first,
thereby allowing catching exceptions that are subclasses of HTTP
exceptions (in ``werkzeug.exceptions``). This makes it possible
for an extension author to create exceptions that will by default
result in the HTTP error of their choosing, but may be caught with
a custom error handler if desired.
- Added :meth:`flask.Config.from_mapping`.
- Flask will now log by default even if debug is disabled. The log format is
now hardcoded but the default log handling can be disabled through the
``LOGGER_HANDLER_POLICY`` configuration key.
- Removed deprecated module functionality.
- Added the ``EXPLAIN_TEMPLATE_LOADING`` config flag which when enabled will
instruct Flask to explain how it locates templates. This should help
users debug when the wrong templates are loaded.
- Enforce blueprint handling in the order they were registered for template
loading.
- Ported test suite to py.test.
- Deprecated ``request.json`` in favour of ``request.get_json()``.
- Add "pretty" and "compressed" separators definitions in jsonify() method.
Reduces JSON response size when JSONIFY_PRETTYPRINT_REGULAR=False by removing
unnecessary white space included by default after separators.
- JSON responses are now terminated with a newline character, because it is a
convention that UNIX text files end with a newline and some clients don't
deal well when this newline is missing. See
https://github.com/pallets/flask/pull/1262 -- this came up originally as a
part of https://github.com/kennethreitz/httpbin/issues/168
- The automatically provided ``OPTIONS`` method is now correctly disabled if
the user registered an overriding rule with the lowercase-version
``options`` (issue ``#1288``).
- ``flask.json.jsonify`` now supports the ``datetime.date`` type (pull request
``#1326``).
- Don't leak exception info of already catched exceptions to context teardown
handlers (pull request ``#1393``).
- Allow custom Jinja environment subclasses (pull request ``#1422``).
- ``flask.g`` now has ``pop()`` and ``setdefault`` methods.
- Turn on autoescape for ``flask.templating.render_template_string`` by default
(pull request ``#1515``).
- ``flask.ext`` is now deprecated (pull request ``#1484``).
- ``send_from_directory`` now raises BadRequest if the filename is invalid on
the server OS (pull request ``#1763``).
- Added the ``JSONIFY_MIMETYPE`` configuration variable (pull request ``#1728``).
- Exceptions during teardown handling will no longer leave bad application
contexts lingering around.