Test connect race with dispatch group and atomic flag
Rearrange atomic checks to remove race
Semaphores revealed
Remove atomic flag
Revert "Remove atomic flag"

As pointed out by @keithduncan, the wait/signal calls need to be balanced,
which was removed by this commit.

This reverts commit 6d4f595c33728915e3a76ff7638a4bc48b699e35.
Merge branch 'multicast-connect-race' of github.com:ReactiveCocoa/ReactiveCocoa into multicast-connect-race-test

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoaTests/RACMulticastConnectionSpec.m
Add comments
Return back to unconditional signalling

This may cause the semaphore to not get released, but a small leak is
acceptable for tests.
Merge pull request #861 from ReactiveCocoa/multicast-connect-race-test

Test connect race with semaphore and atomic flag