[WIP] Use monotonic cubic Hermite interpolation for the NSE table

[zingale]

This addresses an issue where even if the data were all positive, we could get negative values in the interpolation due to undershoots in the existing cubic interpolation.

There is one downside though -- because the limiting is nonlinear, it no longer guarantees that sum{X_i} = 1.

[zingale]

addresses #2072

I need to fix the behavior at the edge of tables.

I also need to deal with the species normalization -- we might just want to drop to linear for the species.

[zingale]

I also need to fix the T derivative of the interpolation. Because we are nonlinear, we need to do things in the same order as the original interpolation and for the final interpolation (now rho), we need to limit on the function values, not derivatives, from the second pass. So this would require a new interface.