This will serve as the basic building block for several comment-related
features.
Task-number: QTCREATORBUG-6934
Task-number: QTCREATORBUG-12051
Task-number: QTCREATORBUG-13877
Change-Id: Ic68587c0d7985dc731da9f539884590fcec764de
Reviewed-by: David Schulz <david.schulz@qt.io>
