Forward ported CLI tests from Flask-CLI and fixed a bug with the CLI's name. (#1806)

* Forward port the CLI tests from Flask-CLI.

* Make sure the parameter passed to the CLI's AppGroup is the app's name, not the app itself.

flask/app.py

@@ -546,7 +546,7 @@ class Flask(_PackageBoundObject):
         #: provided by Flask itself and can be overridden.
         #:
         #: This is an instance of a :class:`click.Group` object.
-        self.cli = cli.AppGroup(self)
+        self.cli = cli.AppGroup(self.name)
 
     def _get_error_handlers(self):
         from warnings import warn