* (widget_destroy): new API to destroy widget.
* (group_del_widget): rename to group_remove_widget. Don't destroy
widget after remove it from group.
Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
WGroup is the base widget for complex objects such as windows, dialog
windows, etc.
Initial steps:
* move widget list of dialog into WGroup class;
* inherit WGroup from Widget;
* inherit WDialog from WGroup.
Signed-off-by: Andrew Borodin <aborodin@vmail.ru>