Liveedit fix

Fix crashes when going to liveedit mode.

Crashes are related to the virtualconsole wigdet map containing too much widgets.

Commit1: loading a project with frames containing widgets will make the widgets appear 2 times in the widget map

Commit2: deleting a frame containing widgets will remove the frame itself from the widget map, not its childrent.
Second version of this patch: #419
This version touches VCWidget::~VCWidget.