The type of electrode projection is now chosable at runtime. There are
currently two types supported:

- normal: project electrodes orthogonally onto boundary intersections
- closest_subentity_center: project electrodes to the closest center of
    subentities of certain codimensions. The codimensions of the
    subentities can be selected at runtime (e.g. project to the closest
    face center, vertex center, edge center or any of those)