Removed three sequencetools functions.

    * sequencetools.iterate_sequence_pairwise_cyclic()
    * sequencetools.iterate_sequence_pairwise_strict()
    * sequencetools.iterate_sequence_pairwise_wrapped()

Use ...

    * sequencetools.iterate_sequence_nwise_cyclic()
    * sequencetools.iterate_sequence_nwise_strict()
    * sequencetools.iterate_sequence_nwise_wrapped()

... instead.