reactive-next

NOT FOR MERGE

This PR is for tracking progress on what will become reactive v1 (once all parties have agreed and code is in a happy place). Lots of this will be lessons learned and code I have already written in a different branch that I will port over to this one cleanly.

- [ ] Adapter per instance
- [ ] "each" iteration
- [ ] no more globals
- [ ] document/readme updates

If you would like to see additional features, please comment on them here and if accepted I will add to the list for v1 target.