[Cin] Mask tool: everything to be done again!

[Andrea paz]

[I'm sorry, I'm kidding :-) ]
The mask tool has become really useful and powerful.
I thank Sam and IgorB for the many inputs and tests; Phyllis for
keeping GG calm [ ;-) ] and everything else; and GG because he is an
incredible coder. CinGG is a great project because you are in charge
of it (not to mention Pierre, MatN, Andrew-R, einhander, Olaf and many
others...).