Develop 245 terminator

[mattldawson]

closes #245

Includes the analytical solution from CAM-Chem in the test for the Terminator configuration.

Also, I updated slightly the logic around min/max/initial solver time steps to avoid changing solver parameters during the solve and to allow users to be able to specify these (which I did in the terminator test to get closer results to the analytical solution).

And, I added the ability to include species whose concentrations are not solved for, but are parameterized on environmental conditions. At first I did this because I mistakenly thought the third-body species "M" was included in the Terminator configuration. I left this option in the PR because it will be useful for other mechanisms that include "M" and for setting constant values for species like O2 and N2

[K20shores]

@mattldawson should we also update the configuration parser to be able to make the parameterized species?

[mattldawson]

@mattldawson should we also update the configuration parser to be able to make the parameterized species?

Yes, I think that makes sense, but I'm wondering how we should go about this, because the open-atmos schema doesn't include this option currently. I feel like this is more of a solver option than a description of the chemical system, so maybe we do a MICM-specific addition to the configuration format?

[K20shores]

@mattldawson should we also update the configuration parser to be able to make the parameterized species?

Yes, I think that makes sense, but I'm wondering how we should go about this, because the open-atmos schema doesn't include this option currently. I feel like this is more of a solver option than a description of the chemical system, so maybe we do a MICM-specific addition to the configuration format?

This feels like something we should add to the open atmos format though. It feels useful