...over change numbers. Add missing "Log project/repository"
actions and log count limits.
Task-number: QTCREATORBUG-503

in annotation editor, including base infrastructure in
VCSBaseEditor. Pass signals of VCSBaseEditor to opaque
VCSBaseEditable (IEditor) for convenience.

Task-number: QTCREATORBUG-503

Make the diff-base directory a property of VCSBaseEditor and use
everywhere.

Match regular expression depending on mode. Improve common VCS settings
layout.
Reviewed-by: Thorbjørn Lindeijer <thorbjorn.lindeijer@nokia.com>