Gravity Tool is a gravity modifying vessel.
It can be a gravity generator, a mass catcher or gravity neutralizer.
Setup:
In scenario file, mode is the mode of operation
(1=mass catcher, 2=gravity generator, 3=gravity neutralizer)
PAR0 is near area of effect in m, PAR1 is far area of effect in m, PAR2 is power of effect in m/s^2