Added support for labelOverflow and parentLabelOverflow.

[Long Ti]

I created a pull request, but didn't respond, so I'll say it again here.

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before:

after:

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[Kevin Armstrong]

I actually saw it but couldn’t perform the request at the time. I’ll do this today.

[Kevin Armstrong]

I also wanted to check with you to see if you’d be interested in collaborating on this widget? I am no longer using it on a current project so I am not able to really push it enough to add new features. I can give you access to perform updates and I can push it to pub.dev.

[Long Ti]

I'm happy to maintain this widget. It is being applied in a project currently working.