[Kst] Kst python scripting/ how to install

[Nicolas Brisset]

> I couldn't reproduce. Have you also set kst_python_build=ON?
No, I must have overseen it. As far as I remember, I set only kst_python=ON.
What's the difference?

On the whole, I'd like to have some feedback on that scripting stuff from packagers. We should check which packages are available for the main distros, and what they support (file formats, scripting, gsl, etc...). It would be a pity if too many packages lack some of the nice optional features.

Nicolas