@Bino: It would be interesting, if there was a way to import textures, on-the-fly with a UE4 HTML5 Export. We could technically create a real time approximate of how the material looks - that would be very interesting.
Thanks guys! Just another little update. Lines are now correctly drawn between each node, added some math to correctly calculate the bezier curves between each (can still do with a bit more work). 
Also just noticed - lines flow under the nodes in the Material Editor. I will fix for the next screenshot
