[PATCH] Scale partial pressure graphs according to enabled gases

[Dirk Hohndel]

subsurface at henrik.synth.no writes:

> From: Henrik Brautaset Aronsen <subsurface at henrik.synth.no>
>
> The max Y value of the partial pressure graph grid tends to be way too
> high when only pO2 or pHe is enabled.

Better, but I think it still gives too much space to a pO2 only scenario

Pushed as is, but maybe we can tune this even more.

/D