Implement the trait Ease for Isometry3d

[TheGrungringMachine]

What problem does this solve or what need does it fill?

Being able to do something like:

let isometry_curve = EasingCurve::new(
            Isometry3d::new(Vec3::ZERO, Quat::IDENTITY),
            Isometry3d::new(Vec3::ZERO, Quat::IDENTITY),
            EaseFunction::CubicInOut,
        )
let isometry = isometry_curve.sample(t).unwrap();

What solution would you like?

Making Isometry3d struct implement Ease. (Not sure what else is needed to make the above code work?)

What alternative(s) have you considered?

Creating a curve singularly for both Vec3 and Quat.

[alice-i-cecile]

We should do the same for Isometry2D.

[RobWalt]

Working on this now!