3.0 - WIP - Added accessor method getView() to ViewVarsTrait.

Let me know if this seems worth pursing.

`AppView` allows setting defaults and then in controller you would use `$this->getView()->foo` to modify stuff as needed. `Controller::$helpers` and similar view related properties would be gone.
Probably better to use [`namespaceSplit()`](https://github.com/cakephp/cakephp/blob/3.0/src/Core/functions.php#L102) here. Changing that function to use `ReflectionClass` will then change it automatically everywhere.