Incorrect calculated variables

[oscarbranson]

Current vectorised fsolve calls in carbon_fns produce incorrect values when multiple parameters are passed. Identified from Luecker et al (2000) test data. Unclear why.

Solution:

• Cast all inputs into ndarray and iterate over rows of inputs. This gives correct results, but is slower.
• When to do this?
  • At [N]sys level, after Ks calculation? Brings problems with identification of None params?
  • But these problems need to be fixed anyway, because at the moment doesn't allow for simultaneous calculation of different input calculations.

[oscarbranson]

Solution implemented at carbon_fns level. Only accepts two C parameters at once - not mixtures of unknowns. I don't think this is a problem.