GEE tidiers

[shah-in-boots]

I see that tidiers in broom::tidy.geeglm() are available, which comes from the original function geepack::gleeglm(). I don't see however the tidiers for gee::gee(), and am wondering if they should be placed here. The gee package itself hasn't been updated in a number of years, and am trying to find the best home for these tidying functions. It looks like there may be a new way to include gee() into parsnip, and it would be nice to have a tidying method for the outcomes.

If its warranted, I'm happy to write them for gee in a pull request as well.

[bbolker]

Since GEEs are often done in a mixed model context, I'd be happy to have them (sorry for incredibly slow response ...)