Plotting helpers

[jonas-eschle]

While zfit itself does not provide plotting functionality, it can still be helpful to provide helpers that do common tasks.

These helpers:

• are limited in their scope and will never cover all edge cases
• very much factorized, e.g. many small functions are favorable over one large
• have awarness for certain PDFs such as the SumPDF in order to plot components (needs a "depth" parameter)
• catch edge cases that a normal user may is not aware of
• if they are too complicated, it's not what we want

The hist package provides already many nice helpers and should be used as far as we can.

Let's keep things 1D for the beginning, other stuff is hard. Maybe a function that just plots the PDF and one that plots pdf and data? The former can also e.g. interpolate using SciPy BSpline (but has to be turned off).

Furthermore, the limits should be taken from .space (or from an argument), there should be an bin argument (or similar) that determines the bins.

Using hist for the binning helps us a lot. We can, for the moment, just think in regular axes.

What do you think?