WinGui: Improved Audio Listbox Item style.  Moved to a single line design.  Since most people generally don't use the DRC, Gain and Sample rate controls, these have been moved into the expandable area instead.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5739 b64f7644-9d1e-0410-96f1-a4d463321fa5