Rockbox Utility: add Speex license to About dialog.

The Speex codec has a special license requiring it to be reproduced with any
distribution.  Add the license as a separate tab in the About dialog to satisfy
this.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30816 a1c6a512-1295-4272-9138-f99709370657
3 files changed