v0.16.0

New features:

• Added CIELAB with D65 standard illuminant, in Cartesian (lab65) and cylindrical (lch65) forms;
• Added interpolatorSplineMonotone2(), a monotone interpolating spline with more sophisticated boundary conditions;

Breaking changes:

• Switch the DIN99o color spaces (dlab and dlch) to use lab65 (D65 illuminant) rather than lab (D50 illuminant), as designed