PK_ERROR_code_t      PK_FIN_ask_type
(
--- received arguments ---
PK_FIN_t             fin,       --- a fin

--- returned arguments ---
PK_FIN_type_t *const fin_type   --- the type of the fin
)


This function classifies the given fin according to the relationship
between its edge and its face.


The fin type classification will be one of:

    PK_FIN_type_wire_c          The edge which owns fin has another fin
                                in the same face, and both fins are in the
                                same loop.
    PK_FIN_type_biwire_c        The edge which owns fin has another fin
                                in the same face, but the two fins are in
                                different loops.
    PK_FIN_type_normal_c        The edge which owns fin has no other fin
                                in the same face.