Photosynthesisers should affect environmental oxygen

[hhyyrylainen]

Split from this issue: #553

• It should be possible for the cell species to affect the amount of oxygen and CO2 (photosynthesisers)

[Untrustedlife]

We dont want this in 0.4.1 ?

[hhyyrylainen]

This wasn't on the list by @TjWhale

[TjWhale]

Yeah I think save this for later.

[TjWhale]

I think this is a bit tricky as it makes the system non-linear, the microbes impact the atmosphere and the atmosphere impacts the microbes so that could make it hard to control. I think maybe it's helpful to test different atmospheric values first with them being constant, then when we know what sort of ranges are fun and work well then add the non-linearity after that.

With the CPA system we tried to jump straight into a non-linear system and we had to backtrack and start again so I'd like to go step by step if possible.