select ring id text on double click

This add a visual feedback to show the ring id has been
copied to the clipboard

Change-Id: I83ea11e8b524d83d3b2183c1a5b62bac4401c7fe
Tuleap: #715

idlabel.cpp

@@ -35,5 +35,6 @@ IdLabel::mouseDoubleClickEvent(QMouseEvent* event)
     Q_UNUSED(event);
 
     QApplication::clipboard()->setText(this->text());
+    setSelection(0, text().size());
 }