[orca-list] orca cannot play multiple progress bar beeps at once

[kendell clark <coffeekingms gmail com>]

hi all
This is an odd bug and I just now noticed it. If you have progress bar
updates set to all, which I'm guessing not many people do, orca can only
play one progress bar beep at a time. If one beep is playing and a
second one comes in, orca will cut the first beep short and play the
second one. I'm not absolutely positive this is an orca but, it might be
gstreamer, but figured I'd report it before I forgot. This is with orca
master, completely up to date and sonar linux 64 bit, version 16.07.
Thanks
Kendell Clark