move My Submissions to primary nav (bug 860373)

Note that only comment #13 (https://bugzilla.mozilla.org/show_bug.cgi?id=860373#c13) is relevant. The discussion around this minor issue got a bit out of hand and was reined back in.
if you're going to include "My Submissions" twice, then include "Submit an app" twice. if you're not going to, then remove the extra "My Submissions" link.