Fix flickering in the project pane.

This isn't a nice fix but the least evil version of a hack i could come
up. The source of the flickering is: We have a deeply nested structure
of widgets on the project pane. If we call hide() on such a deeply
nested widget, it will activate() it's parent layout synchronously.
That will then post an event (via updateGeometries() ) to its parent
layout that it needs relayouting. Which then will post to its parent
layout the same. And for each LayoutRequested, there's a painting in
between. The fix instead calls activate() up the chain until we are at
the viewport. This immediately relayouts everything. This adds a non
obvoius potentially for breakeage if the widgets are embedded in a
different widget hierarchy. But well, that's life.

src/plugins/qt4projectmanager/qt4projectconfigwidget.cpp

@@ -120,6 +120,7 @@ Qt4ProjectConfigWidget::~Qt4ProjectConfigWidget()
 void Qt4ProjectConfigWidget::toggleDetails()
 {
     m_ui->detailsWidget->setVisible(!m_ui->detailsWidget->isVisible());
+    fixupLayout(m_ui->detailsWidget);
 }
 
 void Qt4ProjectConfigWidget::updateDetails()