ReactiveCocoa/ReactiveCocoa — pull request #374 by jspahrsummers (2013-03-13 08:03:50+00:00)
Title: Hide RACCommand's subscriber behavior in a private RACSubject

Fixes #373.

Although this changes the `RACCommand` interface, the "removed" functionality has been marked `deprecated` (but will still work), and never really should've been used in the first place.