Fixes #10350

Fixes #10077

Should be reverted when https://github.com/flutter/flutter/issues/6577
is fixed.

Adds a widgets that blocks all semantics of widgets below it in paint order within the same container (#10425)

Adds support for requesting keyboards optimised for email address and URL entry.

Fixes https://github.com/flutter/flutter/issues/10424

* Small setup doc for the app store option

* review notes

This prevents some of our mixins from being subclassed.

Also, move mixins to using 'extends' instead of 'implements' for
future compatibility with Dart changes.

Also, rename a class that had Mixin in the name but was not a mixin.

* add min version checks for IntelliJ

* validate the installed versions of IntelliJ and the flutter plugin

* review comments

* have app loggers log to their parent logger

* rename field to parent

* add todo

* revert flutter_tools.iml change

* ping the bots

Picks up accessibility fixes.

* preview of prefer_asserts_in_initializer_list lint

* fix issue

Create a CupertinoNavigationBar without automatic adding of the lead button

Extract layout logic in material app bar to a common file that can be reused for cupertino

* (Update and) Integrate Rendering README into code

* Add mising whitespace

* Review comments and other touch-ups