Fix creation of float arrays

[vouillon]

Fixes #112.

[rickyvetter]

Tested this locally and it works well. Thanks!

[rickyvetter]

Offering a slighly more thorough test that also covers the getter and setter code paths:

let construct x = [| x |]

let get (x : float array) = x.(0)
let get_ (x : _ array) = x.(0)

let set (x : float array) e = x.(0) <- e
let set_ (x : _ array) e = x.(0) <- e

let a = construct 1.0

let _ = set a 2.0

let _ = assert (Float.equal (get a) 2.0)
let _ = assert (Float.equal (get_ a) 2.0)

let _ = set_ a 3.0

let _ = assert (Float.equal (get a) 3.0)
let _ = assert (Float.equal (get_ a) 3.0)

let b = [| 1.0 |]

let _ = set b 2.0

let _ = assert (Float.equal (get b) 2.0)
let _ = assert (Float.equal (get_ b) 2.0)

let _ = set_ b 3.0

let _ = assert (Float.equal (get b) 3.0)
let _ = assert (Float.equal (get_ b) 3.0)

[vouillon]

Thanks!