ReactiveCocoa/ReactiveCocoa — pull request #874 by jspahrsummers (2013-10-18 08:43:15+00:00)
Title: [WIP] Replace commands with simpler alternatives

**:warning: NOT READY TO MERGE :warning:**

As described in https://gist.github.com/jspahrsummers/7000136, I'd love to break down `RACCommand` into a few simpler, more independent pieces.

Of course, `RACCommand` will continue to exist for backwards compatibility, but I'm hoping we can provide enough power in these new primitives to avoid it entirely.

**To do:**

- [x] `RACSubject`
- [ ] RefCount
- [ ] Enabled/disabled operator
- [x] Kleisli arrows