Bug Fixes and Whitespace changes

Fixed two bugs: 1) check for null defaultAudioDevice needed in
getAvailableAudioDevices 2) SetDefaultOutputDevice(string deviceName,
string busName) was calling wrong function. Not sure what happened but
it appears the whitespace was changed. Original whitespace did not
appear aligned in git's diff program though so consider this also a good
update. A good diff program should negate whitespace changes and allow
you to see bug fixes. Not sure if github's diff supports that option.