MacGUI: Refactored the controller code for the video/audio/subtitles/chapters view:
Added a xib file and a NSViewController subclass for each tab of the main HandBrake window.
Each view controller now to responds to the HBContainerChangedNotification and HBTitleChangedNotification notifications instead of using a custom way to notify changes.
Converted the modified .xibs to the Xcode 5.1 format.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6231 b64f7644-9d1e-0410-96f1-a4d463321fa5