MacGui: Audio Fixes and Enhancements ... patch by circleone.

MacGui: Audio Fixes and Enhancements ... patch by circleone.
Fixes issue where changing to custom from a preset then changing titles will cause an empty audio tab.
Also:
- Added the ability for HandBrake's language preference to be honored when it occurs in the title's tracks.
- Ensured the limit (currently 24) is not passed when adding audios using presets.
- If no preset is chosen, when a new title loads, one track is added (based on the language preference or the first if that is not met).
- Reinitializing the audio array is now KVO-friendly, making the UI refresh more pleasant.
- The "Add All Tracks" button has been made mini in size.
- The audio table view no longer attempts to keep the selection.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@3549 b64f7644-9d1e-0410-96f1-a4d463321fa5