Re-added and fixed AAC support

To be honest, I'm not entirely sure why this was commented out. Only one line was needed to fix it and that line exists upstream (mattgallagher/AudioStreamer).

Was it because the iOS simulator used to throw a fit with this and used to require an `#ifdef !TARGET_OS_SIMULATOR`? Or was it the `formatList` memory leak? Either way, they're fixed now and I can't find anything broken with this.