Add missing calls to super class "__init__"s (#1693)

* FIX : Add missing call to __init__ in super class

* FIX : Add missing call to __init__ in super class

* FIX : Add missing call to __init__ in super class

* FIX : Add missing call to super __init__

and fix a flake8 error

	modified:   traitsui/editors/array_editor.py
	modified:   traitsui/qt4/ui_panel.py

* DEV : Undo change in qt4 GroupEditor

see #1674

	modified:   traitsui/qt4/ui_panel.py

* CLN : Pass args to __init__ call

Previously, we were setting traits/attributes before calling __init__ on
the objects, which setup the traits machinery. Instead, this commit
passes the arguments to __init__, which feels like the right thing to do

	modified:   traitsui/editors/array_editor.py
	modified:   traitsui/editors/tuple_editor.py
	modified:   traitsui/qt4/ui_panel.py

traitsui/editors/array_editor.py

@@ -55,8 +55,7 @@ class ArrayStructure(HasTraits):
     def __init__(self, editor):
         """ Initializes the object.
         """
-        # Save the reference to the editor:
-        self.editor = editor
+        super().__init__(editor=editor)
 
         # Set up the field width for each item:
         width = editor.factory.width

traitsui/editors/tuple_editor.py

@@ -113,15 +113,14 @@ class TupleStructure(HasTraits):
     def __init__(self, editor):
         """ Initializes the object.
         """
+        super().__init__(editor=editor)
+
         factory = editor.factory
         types = factory.types
         labels = factory.labels
         editors = factory.editors
         cols = factory.cols
 
-        # Save the reference to the editor:
-        self.editor = editor
-
         # Get the tuple we are mirroring:
         object = editor.value
 

traitsui/qt4/ui_panel.py

@@ -102,7 +102,8 @@ class _Panel(BasePanel):
     def __init__(self, ui, parent, is_subpanel):
         """Initialise the object.
         """
-        self.ui = ui
+        super().__init__(ui=ui)
+
         history = ui.history
         view = ui.view