Negative Group Numbers

[Joe Riel <joer@xxxxxxxxxxxx>]

It would be convenient if negative group numbers were allowed.
FEMM doesn't balk when they are entered; however,
the groupselectblock command doesn't select any blocks with negative group numbers.

The reason that this would be convenient is that
it simplifies the task of assigning directions to currents in a planar analysis.
For example, I would like to assign group numbers of +n and -n to the two ends
of the conductor(s) that make up winding n.

Joe Riel