Add sex-specific model parametrisations

[MichaelClerx]

Yang, P.-­C., Kurokawa, J., Furukawa, T. & Clancy, C.E. Acute
effects of sex steroid hormones on susceptibility to cardiac
arrhythmias: a simulation study. PLoS Comput. Biol. 6, e1000658
(2010).

Yang, P.-­C. & Clancy, C.E. In silico prediction of sex-­based
differences in human susceptibility to cardiac ventricular
tachyarrhythmias. Front. Physiol. 3, 1–­12 (2012).