MacGui: Increase width of main window from 754 to 960

MacGui: Increase width of main window from 754 to 960
- Increases the main window width from 754 to 960 which is an increase of 206 px. This allows more breathing room for some crowded tabs like Audio, Subtitles and Advanced. Also increased the associated views. The main prompt for this is the very crowded audio tab which recently added Gain and also could use a vbr checkbox as well as possibly an aname field. I would rather maximize the width we deem available before going to an advanced audio track popup like the lingui and wingui currently utilize.
- For now any widgets have been expanded to their nearest longest known value without truncating.
- As per review board https://reviews.handbrake.fr/r/116/

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@4036 b64f7644-9d1e-0410-96f1-a4d463321fa5