CppEditor: Extract CppLocalRenaming

Now CppEditorWidget is much less convoluted with the local rename mode.

This class can be reused since there is no dependency on
CPPEditorWidget.

Change-Id: If513e59a03214cf9f2e3831f7e3616c001e1f036
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
CppEditor: Extract CppEditorOutline

Change-Id: I3b41f91f17ce9fb24796f2f6bff353fb3c6177ec
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
CppEditor: Respect navigation history when using cppeditor outline

Task-number: QTCREATORBUG-12281
Change-Id: I95aef60943ec76dd035914e0d13aef7b8db8e211
Reviewed-by: David Schulz <david.schulz@digia.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
CppEditor: Extract CppDocumentationCommentHelper

Change-Id: Iefaff837565f0aaf7e52263daa40a58fc391df36
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>