The values for consUl, delta_iR, lambdaI.sel, M_t_1, and PMF have all
been updated in response to feedback from our clinical collaborators.

The reticulocyte release rate function (rho) has also been changed, and
introduces two new parameters (rho_slope and rho_inflection).

The sensitivity analysis outputs are not updated in this commit, and
will need to be regenerated when we're satisfied with this new parameter
baseline.