Doc: Removed link to the Double Buffer example.
Doc: Removed link to the Double Buffer example.

-Code no longer exists in the repository.

Change-Id: I4a705ac9ce9afc6c923f4bc31b5b924fad0ce80b
Reviewed-by: Paul Olav Tvete <97541fb6312d77f06e19078c7c70b2c1f75fb828@nokia.com>
Reviewed-by: Martin Smith <a8cc6484db2755056ccf1c457da8ca771f895dea@nokia.com>

kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc