The GroupView is a editable object view on workspace. This widget should display the special editable object for Group. Widget should:
- calculate the padding for part that stands out
- select part by click
- emit signals for events, 'mouse,in', 'mouse,out' for each part
- send message about where cursor now, means that widget send message with part name over which cursor now
- calculate part geometry and paddings for it related to editable object geometry
- calculate object area geometry and paddings related to editable object goemetry