The function convert_straight_skeleton_2 converts a straight skeleton instantiated using certain traits into another straight skeleton instantiated using a different traits.
convert_straight_skeleton_2 ( Source_skeleton s, Items_converted ic = Items_converter())
returns a new straight skeleton data structure with the same combinatorial and geometric data as using the items converter to convert the geometric embedding to the types of the target skeleton.
The first template parameter is the type of the target straight skeleton. This template parameter is not bound to a function argument so it must be explicitly specified.
