Provide an equality check function instead of messing with class hierarchies

[Grohden]

This package seems great, is just what I need, but unfortunately I have to change my classes hierarchies to be able to use it

It would be nice to have a equality check function passed as a prop to the widget instead of adding a new class hierarchy

Btw, I'm using a personal custom modified version of the package just so I can get rid of the taggable class, if you wish I could make a PR

[bradintheusa]

Can you make a PR? I would be interested in that.

[Grohden]

@bradintheusa I'm not sure if I will be able to open a PR in the near future..

But you can take a look at my changes and open a PR if you wish: https://github.com/Grohden/repo-tagger/blob/master/frontend/lib/external/taggable/tagging.dart

Edit: I called the equality check prop areObjectsEqual