Add function curve_plot
read_cfg.py : Cosmetic modifications in displayed text
Add demo CSV file and modify easy_plot.cfg for it
read_cfg.py : DEFAULT_[MIN, MAX] set to None
Creation of main function

This function let the user to plot curves from a CSV file.
(minY, maxY) -> (MinY, MaxY)
The main example use a fake Enslavment test
The main example is not a lot more faster