plot_tight_variables: add plot per source
add isTightPp to faketuple
utils: mkdir -> makedirs (also works for nested dirs)
fakeu: elecIsTight, also require tightPP
fakeu: define tuple stems and names
SampleUtils, add some protection
plot_tight_variables: add a bunch of features and plots
compute_fake_el_scale_factor: mode -> region, plot also tight; print info