ReactiveCocoa/ReactiveCocoa — pull request #326 by scutdavy (2013-02-14 02:09:26+00:00)
Title: modification to support iOS 4.3

to support ios 4.3, I just use ` unsafe_unretain` instead of `weak`; and disable the `+load()` method in `RACBacktrace`; and workaround for ios5 only function `dispatch_queue_set_specific`. Wound you please review for these modification and any advice will be very appreciated.

thanks for your reading.