PlugValueWidget : Parent popup menus to self
PlugValueWidget : Parent popup menus to self

This allows menu items to find the widget with `ancestor( PlugValueWidget )`.

johnhaddon/gaffer,appleseedhq/gaffer,hradec/gaffer,GafferHQ/gaffer,boberfly/gaffer,boberfly/gaffer,appleseedhq/gaffer,GafferHQ/gaffer,lucienfostier/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,GafferHQ/gaffer,ImageEngine/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,hradec/gaffer,boberfly/gaffer,lucienfostier/gaffer,boberfly/gaffer,johnhaddon/gaffer,hradec/gaffer,andrewkaufman/gaffer,andrewkaufman/gaffer,lucienfostier/gaffer,hradec/gaffer,appleseedhq/gaffer,GafferHQ/gaffer,ImageEngine/gaffer,ImageEngine/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,ImageEngine/gaffer,hradec/gaffer,lucienfostier/gaffer