Correct inductor
- Corrected 3D geometry: issues with the use of Boundary and CombinedBoundary and the removal of some surfaces of the boundaries of the (conducting) cores. Function Abs() has been added.
- New 3D geometry generated with opencascade tools.
- Adding the possibility of weakly imposing div j=0 for the source. It seems to be necessary with the tree-cotree gauging and the old geometry. The new geometry and mesh does not seem to be so 'touchy'.