Prevent joining onto itself already on the client side. Closes #341
Prevent joining onto itself already on the client side. Closes #341

fzadow/CATMAID,htem/CATMAID,htem/CATMAID,fzadow/CATMAID,fzadow/CATMAID,htem/CATMAID,fzadow/CATMAID,htem/CATMAID