Include function to apply a Mat4 to a Vec4

[exists-forall]

The Matrix4 module currently includes a function transform for applying a Mat4 to a Vec3, but no function for applying a Mat4 to an arbitrary Vec4. I'm using this package for some calculations involving four-dimensional geometry, so having this function would be extremely useful!

[JEphron]

+1, this operation comes in handy when doing ray-casting.
I'm currently using the following function in my own projects:

transform4 : Mat4 -> Vec4 -> Vec4
transform4 mat vec =
    let
        { m11, m21, m31, m41, m12, m22, m32, m42, m13, m23, m33, m43, m14, m24, m34, m44 } =
            Mat4.toRecord mat

        { x, y, z, w } =
            Vec4.toRecord vec
    in
    Vec4.fromRecord
        { x = m11 * x + m12 * y + m13 * z + m14 * w
        , y = m21 * x + m22 * y + m23 * z + m24 * w
        , z = m31 * x + m32 * y + m33 * z + m34 * w
        , w = m41 * x + m42 * y + m43 * z + m44 * w
        }