v2.010002

  - Fix array->sliced() to avoid backfilling undefs if requesting position(s)
    past the end of the array

  - Fix array->insert to backfill undefs if inserting to a position past the
    end of the array

  - Fix array->rotate on an empty array

  - Fix array->delete_when to localize *_ (not $_) for consistency

  - Expand regression tests for empty array behavior