...in response to CR, move the AudioService off of the CallViewController
Adopt multiple observer pattern vs. a singular delegate. Doing so
required implementing some machinery to address the ARC (see:
Weak.swift)
// FREEBIE
Implement speakerphone toggle directly. Previously we were using
AppAudioManager for several things, but this is that last lingering bit.
Much of the AppAudioManager code is based on RedPhone calling, so by
removing the dependency we pave the way to throw that code away.
// FREEBIE
