Big rework of cell structure display: Many new figures, restructured plotting section, introduced a new subcell section.

Cleaned up and finished some python scripts.

Also cleaned up the info and warning boxes. If you want icons again, they should be inserted differently.

The whole document needs a bit more structure and probably better colors.

* Scheme PDE clarification and structurization
* Text about the NCP
* Several design notes about the NCP and the plotters
* Introduced a list of authors, figures, tables