Working SVG output

Previously worked with png output for simplicity of previews.
This has at least two downsides:

1. Resolution dependent - especially cumbersome when combining different graphics
2. Potentially large filesizes - not that easy to share.
   For example:
   combined1..11 from results41.7z: 5.6MB
   all part-images from example41SVG.7z: 9 KB

TODO:
Potentially size-constraint on large solutions
Layout the primal nodes (ex. in a circle)
Find way to combine the .svg into one image.