MacGui: Queue - Display varying row heights based on the content of the encode.

- Accommodates varying numbers of subtitles and audio tracks as well as optional lines based on encode settings.
- fixes issue where many audio tracks and subtitles can cause the bottom part of the expanded view to get cut off.
- Note: seems to be a bit of extra padding especially when using many subtitles, may want to adjust that at some point.

git-svn-id: svn://localhost/HandBrake/trunk@2603 b64f7644-9d1e-0410-96f1-a4d463321fa5