Install dependencies on TravisCI to enable more features
Install dependencies on TravisCI to enable more features

Install Ubuntu development packages for PulseAudio, PortAudio, ALSA and
JACK to enable the building of most Linux backends on TravisCI.

Intall Ubuntu development packages for Qt5 to enable `alsoft-config`.

aaronmjacobs/openal-soft,aaronmjacobs/openal-soft