Hello maintainers of the amazing package,

I recently updated cobrapy and am experienced unexpected behavior with cobra.test.create_test_model("salmonella")

Two things are unusual:

1. Now, many warnings are given during loading of the model, whereas none were given in a previous version. Here are a few of the warnings:

`Model does not contain SBML fbc package information.
SBML package

It would help to have download option to get a list of used packages:

For example:
Download list of ML Packages used in Model Training, with all corresponding citations in CSV Format.

Matplotlib offers various ways of defining colors, in particular via the standard colors cycle ('C0-10'), as hex or as a RBGA tuple https://matplotlib.org/3.1.1/tutorials/colors/colors.html. If I see it correctly, the pypesto visualization routines currently only allow RGBA values. It would be preferable to allow for any color input. This should be rather easily possible by rewriting how passed co

Use the tempfile....File context managers with delete=True, and yield results in between if necessary.