Work around OS X bug in which the Credits text is not centered.

<http://www.openradar.me/14829080>
Update Credits and convert to UTF-16 (UTF-8 doesn't work).
Tested on 10.7 - no flashing necessary.
Sign with Developer ID for Gatekeeper on OS X 10.8.
Use OS X 10.8 SDK explicitly.
Handle the dock tile plugin, or (more likely) not.
Shroud 1.2