Function interpolate

interpolate(
    v0: number,
    v1: number,
    easing: (ti: number) => number,
    t: number,
): number
Perform interpolation of scalars with an easing function. The easing function transforms linear change into change that may accelerate, oscillate, etc., and that may not be bounded or endpointed by v0 and v1.

For example:
```
interpolate(0, 1, t => t*t, 0.6) = 0.36
interpolate(0, 10, t => t*Math.cos(2*Math.PI*t), 0.4) ≈ -3.236
```
Parameters
- v0: number
  value when easing(t) = 0
- v1: number
  value when easing(t) = 1
- easing: (ti: number) => number
  function mapping input interpolation parameter ti, 0 <= ti <= 1, to an applied interpolation parameter, unconstrained
- t: number
  input interpolation parameter
Returns number
the linear interpolation along v0 to v1 at easing(t)

Throws
Error if t < 0 or t > 1