Sunburst fixes

[ialarmedalien]

This fixes #1467, the absent transitions in the sunburst chart. Includes an edit to safeArc to reorder params and remove the unnecessary i argument.

[tttp]

Hi,
Why did you upgrade grunt? is there something incompatible with the existing version?

[ialarmedalien]

I ran npm audit fix after installing the various node modules as there were a number of security issues flagged; the updated grunt is probably a result of that. (Rerunning it reveals a further 27 security vulnerabilities, including six serious ones.)

[gordonwoodhull]

This works very well! Thank you, I hope to merge this soon.

I find the history of this branch a little confusing, so I think I will just take the last commit (ccbf7c2), and do the npm updates separately. Seems to work!

Although it is important to stay up-to-date, we generally aren't exposing our users to any security vulnerabilities - these flaws invariably arise on the devDependencies side, so we may have insecure testing environments, but that's not a big deal. I don't think anyone is putting our grunt server into production. (I hope not!)

[gordonwoodhull]

Thanks @ialarmedalien! This looks amazing, and really helps see what just happened when you filter.

Merged for 3.0.7