Fixed -switchToLatest completing when the latest child signal hasn't completed yet.
Update -if:then:else: tests.
Use RACSignal constructors.
Remove use of anonymous @synchronized.
No need for Orig here.
Flip the branches around.
Use Increment and Decrement.
Merge pull request #352 from ReactiveCocoa/fix-switchtolatest

Fixing -switchToLatest not mirroring Rx.