If the input field was a vector field (i.e. had 3 components) and
if ComputeVorticity was set, the output would be the vorticity
INSTEAD of the gradient. If ComputeQCriterion was set, this was output
as a separate field. Changed it so that ComputeVorticity is output
as a separate field now as well. Also each of the outputted fields
can have their names set.

Change-Id: Ia7d85a8e1706561311aeaed7aded9d0a2d36fc41