A user complained about the default cylinders list. Provide
a preferences option to turn this off.
When changing the preferences, the tank-info model will be
completely rebuilt. Currently, this is a bit crude as this
will be done for any preferences change.
Suggested-by: Adolph Weidanz <weidanz.adolph@gmail.com>
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>