fixed a formatting error around the data upload tip sheet link; added a link to the join us page; fixed all links so that logged in users are treated as user=Guest and therefore stay in the guest area
fixed a formatting error around the data upload tip sheet link; added a link to the join us page; fixed all links so that logged in users are treated as user=Guest and therefore stay in the guest area


paleobiodb/pbdb-new,paleobiodb/pbdb-new,paleobiodb/pbdb-new,paleobiodb/pbdb-new,paleobiodb/pbdb-new