Beamer-friendly version of the graphs

[rappatoni]

Frequently, when displaying theory graphs on a beamer, the light gray edges frequently are not visible. The color scheme should be adjusted to be more salient or there should be a beamer mode that does so.

[kohlhase]

Either that (i.e. to permanently change the colors to be more "into-your-face") or have a button somewhere that turns on "beamer-mode".
Actually, this is very important for demos, which regularly fail because of the invisible connections. I just always forgot, so thanks to Max for bringing it up.