Modulo by Arrow compute function

[heronshoes]

Vector#modulo and #% follow Ruby's behavior.
(Using #floor)

class Vector
  def modulo(divisor)
    divisor = divisor.data if divisor.is_a?(Vector)
    d = find(:divide).execute([data, divisor])
    d = find(:floor).execute([d]) if d.value.is_a?(Arrow::DoubleArray)
    m = find(:multiply).execute([d, divisor])
    datum = find(:subtract).execute([data, m])
    Vector.create(datum.value)
  end
  alias_method :'%', :modulo
end

#remainder also follows. This is Numo::NArray's #% method.
(Using #trunc)

 def remainder(divisor)
   divisor = divisor.data if divisor.is_a?(Vector)
   d = find(:divide).execute([data, divisor])
   d = find(:trunc).execute([d]) if d.value.is_a?(Arrow::DoubleArray)
   m = find(:multiply).execute([d, divisor])
   datum = find(:subtract).execute([data, m])
   Vector.create(datum.value)
 end
 ```

[heronshoes]

Resolved #101 .