Add failing test for HotSignal.pipe() lifetime
Add regression test for observe() lifetime
Add regression test for observe() disposable
Add regression test for HotSignal disposal
Add test for HotSignal generator lifetime
Refactor pipe() so the sink keeps its signal alive
Try with a longer timeout (i dunno lol)
Remove non-nil test for innerSignal

Maybe that lengthened its lifetime erroneously?
Merge pull request #1589 from ReactiveCocoa/hot-signal-lifetime

Refactor HotSignal.pipe() so the sink keeps the signal alive