Edge stroke gradients and contribution changes

[LacombeJ]

Hi, I noticed that edge stroke gradients functionality is in the code but is commented out. Is there a reason why?

I have been working on port and edge coloring and found that I've been making some small changes to GraphViewBase to get things working. Is this repo open to submit pull request?

[Doppelkeks]

Uh, good question. If I remember correctly, it was just not needed at the time for NewGraph. I really appreciate any pull request, so send them in and I'll check if the pull request is compatible. :)

[LacombeJ]

@Doppelkeks I submitted a PR. There could be possibly more work to be done since Edge.cs currently resets InputColor and OutputColor on edge selection. In my graph editor I override this to only set EdgeWidth on selected but I didn't touch this since NewGraph styling relies on this.