MacGui: Scale > 720 or > 480 Picture Previews and the Picture Settings window to...

MacGui: Scale > 720 or > 480 Picture Previews and the Picture Settings window to fit to screen.
- Perfect for HD transport streams or any HD source
- If source width is > 720 or source height is > 480, the Picture Settings window will scale appropriately to 85% of either the users screen height or width, whichever it runs into first.
- The scaled size for the preview is displayed in the Picture settings detail at the bottom as a percentage.
- Thanks blindjimmy !!

git-svn-id: svn://localhost/HandBrake/trunk@965 b64f7644-9d1e-0410-96f1-a4d463321fa5