In the cylinder table, the last column ("use") always showed
OC-GAS. Editing was enabled, but the user had to guess to enter
a small integer meaning dilluent or CCR oxygen cylingder. I guess,
nobody has ever done that.
This patch makes this column clickable. A click toggles if the cylinder
is used for planning or not. This wait it is much easier to investigate
the consequences of gas loss on a plan.
Signed-off-by: Robert C. Helling <helling@atdotde.de>