Polar coordinates
- Added functions to switch from Cartesian to polar coordinates and vice versa.
- Implemented functions to add planes at constant r or phi and to enter wires in polar coordinates, and to add strips or pixels on r or phi planes.
- When calculating the electric field or weighting field, a transformation of the input (Cartesian) coordinates to log-polar coordinates is applied, and the components of the electric field are subsequently transformed back to Cartesian coordinates.
- Bug fix in the transformation of wire coordinates to the basic cell.
- Adapted ViewCell for the visualization of circular and phi planes.