Leak in AudioPluginHost demo

Steps to reproduce (OSX):

- Run the Plugin Host

- Press cmd + A

- Press cmd + Q

Cheers :)

It's just a demo app! Not every edge-case has been thought about, to say the least!

The audio dialog actually needs to be rewritten so that it's non-modal too. We'll probably actually revamp that whole example project soon anyway.

Of course, that's what I thought too!