Major 4.0 update in development

[brendan-duncan]

It's been nearly 10 years since I wrote this library. Dart has changed a lot since then, and Flutter didn't even exist. Looking over this library, there are a lot of things I would have done differently. So I decided to do a full redesign.

I don't have a release date yet. There's a lot of code to go over. But the redesign includes a new Image class that supports arbitrary bit-depths, formats, number of channels. It will result in less memory and more flexibility. I'm also using it as an opportunity to clean up the code and API.