Switches to soundmanager instead of audio-js.
Merge branch 'sound_manager' of https://github.com/rtibbles/ka-lite into sound_manager
Updated soundmanager with user-facing GUI and progress tracking.
Don't show "None" for descriptions (more debugging needed).
Removed unused bar-ui.js file.
Merge pull request #2480 from jamalex/sound_manager

Updated audio player to use SoundManager 2
Have the top left KA Lite icon redirect to the /learn/ tab for now.
Merge pull request #2481 from jamalex/sound_manager

Have the top left KA Lite icon redirect to the /learn/ tab for now.