Fixed typo in saturation density imposed notebook

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Added NR code for density imposed saturation routines

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
sat_d now uses log(delta)

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Added keyed_output function

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Added check for saturation two-phase or single-phase

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Added functionality for Tmax and pmax

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Fixed typo in sat_d derivation

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Fixed typo in derivative for sat_d_pure.  Added ability to use log(delta) instead of delta as independent variable. Doesn't seem to help that much.

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Tests now also prints inputs for the other two variables

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Added high level integration code - a hacked version of PropsSI is now working.

Signed-off-by: Ian bell <ian.h.bell@gmail.com>