draw_fit: name of h_sum_fit.
eta_bkg switch from config.
Default find_f_dz=0.
fluctuate_toys_shapes, which is on by default, and default sig_eff_uncert=0.2.
Defaults in code.
Don't hardcode -9 index for pval_signif; fix limit_bracket pval_signif naming; _shortened plots.
Split into base_ and not for play scripts.