R/plot-MYZ.R
    dts_lines_YZ_fracs.RdAdd lines for the fraction of infected and infective mosquitoes
dts_lines_YZ_fracs(MYZ, pars, Yclrs = "purple", Zclrs = "darkred", llty = 1)a list the output of ramp.dts::parse_deout()
a list that defines an ramp.dts model (e.g.,  generated by dts_setup())
a vector of colors for infected mosquitoes
a vector of colors for infective mosquitoes
an integer (or integers) to set the lty for plotting