display.sh: made separator() more harmonious

lib/display.sh

@@ -131,6 +131,9 @@ separator()
     echo -ne "$BYellow"
     local i=0
     declare -li length=$(( $(tput cols) - 1 ))
+    if [[ $length -gt 80 ]]; then
+        length=$(( $length - (($length - 80) / 2) ))
+    fi
     for i in $(seq 1 $length); do
         echo -n "-"
     done