Attempt to enable dummy sound device on travis
Attempt to enable dummy sound device on travis

It's not clear online on if this will actually work or if it's
disabled on Travis. It definitely was disabled in 2014, according to
this issue https://github.com/travis-ci/travis-ci/issues/1754, but the
comments at the bottom imply it may work now.

JWorthe/rusty_microphone,JWorthe/rusty_microphone,JWorthe/rusty_microphone