update XSTRs

git-svn-id: svn://svn.icculus.org/fs2open@10541 387891d4-d844-0410-90c0-e4c51a9137d3
tweak dialog box

git-svn-id: svn://svn.icculus.org/fs2open@10542 387891d4-d844-0410-90c0-e4c51a9137d3