Passing arbitrary arguments to the solvers

[areleu]

Hi! We are testing out https://github.com/rust-or/good_lp and to use solvers such as gurobi we need to use your API, to do proper testing we needed to adjust the arguments passed to the solver and I couldn't find an API to do this so I implmenented a hack here https://github.com/areleu/lp-solvers/tree/verbose-gurobi which I consider not viable in the long run because this would mean adding a method for every single command.

Am I missing some part of the documentation or is this a missing feature?