Cleans SC.TextFieldView.
Uses isEnabledInPane of SC.Control mixin to determine whether to add disabled attributes to the input field or not.
Cleans up the code of SC.TextFieldView and SC.FieldView slightly. Notably removing double attempt to set disabled attribute on the input inside SC.TextFieldView (it’s set by SC.Control) and not setting the mouse state flag and becoming first resonder on mouse down when the text field view is disabled and not notifying that the selection has changed on mouse up when the text field view is disabled.
Fixes the problem that changing the isEnabled value of a view which had disabled ancestors could change the value of isEnabledInPane for the view to an improper value.