Hans Goudey
675677ec67
First, expand on the interpolation to evaluated points with a templated helper function, and a function that takes a GSPan. Next, add a set of functions to `Spline` for interpolating at arbitrary intervals between the evaluated points. The code for doing that isn't that complicated anyway, but it's nice to avoid repeating, and it might make it easier to unroll the special cases for the first and last points if we require the index factors to be sorted.