contribute.ctp: added links that are in the sub-menu. The links in the dropdown menu are for some reason not clickable.
contribute.ctp: added links that are in the sub-menu. The links in the dropdown menu are for some reason not clickable.

git-svn-id: 776ea4b3e47339c5b8782ec5e9346c740e073fb4@1830 e0e46c49-be69-4f5a-ad62-21024a331aea

hans/tatoeba2,hans/tatoeba2,hans/tatoeba2