Split selected segments, resulting in two adjoining segments of
the same type. The geometric location at which the split takes place cannot
be specified by the user. It is possible to move the join-point afterwards.
The segments to be split are selected using the blue control points.
If segments of a component of type path are split, then the identity of the component
is maintained. If a component of type line, arc or circle is split, a new path-component
will be created and the original component is removed.