Add bindings for saturnin clipboard manager

dotfiles/i3/config

 bindsym $mod+Shift+Return   exec "xfce4-terminal"
 bindsym $mod+b              exec "ub -1"
 bindsym $mod+Shift+b        exec "saturnin conf -j -S www.conf | saturnin dmenu -l 20 --split = | xargs -r ub -a"
+bindsym $mod+c              exec "saturnin clip save"
+bindsym $mod+Shift+c        exec "saturnin clip load"
 bindsym $mod+Shift+f        exec thunar
 bindsym $mod+Shift+o        exec "urxvt -e mocp"