This can play anything that AWavLoader can load (so obviously only WAV
files at the moment.)
It works by having a timer that wakes up every 100ms and tries to send
a sample buffer to the AudioServer. If our server-side queue is full
then we wait until the next timer iteration and try again.
We display the most recently enqueued sample buffer in a nice little
widget that just plots the samples in green-on-black. :^)
