interpol – Add interpolation to METAPOST graph package

This file declares a new internal quantity interpolating and modifies the augment and Mreadpath routines of the METAPOST graph package (part of the base METAPOST distribution) to construct a path from data points using Bezier curves instead of polygons (line segments) when interpolating is set positive.

Use of this feature can lead to severe distortions if the data isn't suitable. Its usefulness may best be seen when plotting smooth functions evaluated numerically at discrete intervals.