Compose sequences for o-double-acute.


git-svn-id: svn://svn.tartarus.org/sgt@10198 cda61777-01e9-0310-a592-d414129be87e
Add o with double acute accent.

As a mathematician, it's important to be able to type Erdős!


git-svn-id: svn://svn.tartarus.org/sgt@10199 cda61777-01e9-0310-a592-d414129be87e