Added missing comma
Add constructor comment for widget model.
Update option-passing for creating child views.
this.updating should be a key specific lock
s/BaseWidgetView/WidgetView and s/WidgetView/DOMWidgetView
un-nest options.options
Make the default model the WidgetModel

For the vast majority of python widget classes, this means that you no longer need to specify the target_name, as a perfectly good WidgetModel instance will be created for you (inherited from the base widget class).