HermeneutiX: Export with specific background color

[CarstenWickner]

As a HermeneutiX user I want to be able to set the background color for the generated SVG files instead of the default (transparent), in order to have this additional customisation option.

Thanks to Phil (@j2l) for the suggestion.

[CarstenWickner]

While this one seems simple enough, I'd deem it to be a low priority for now, as you can always put some monochrome background behind the SVG with transparent background. The background of the propositions and the other colors you can already configure.
I.e. I might be introducing this on the side while doing something else, but otherwise I'd not dedicate any time for this in the near future.