Function rgbaNearestInterpolation

rgbaNearestInterpolation(point: VectorPoint, refData: VectorPoint<RGBA>[]): RGBA
Helper function for nearestInterpolation on RGB(A) data. Light in RGB data is logarithmically weighted, so we need to expand each component by n^2 to get the correct weight for each component.
Parameters
- point: VectorPoint
  Point to interpolate
- refData: VectorPoint<RGBA>[]
  Reference data points
Returns RGBA
- The interpolated RGBA data.