Omit unused table slot

By putting \omit entries in the table slots that are not used, the
template is left out, which means that we don’t get leader dots
across the empty space.

colour.tex

@@ -64,7 +64,7 @@
 \ct{1.00}{0.53}{0.37}{Staedtler red}& 209 & \ct{0.37}{0.84}{0.00}{Koh-i-noor green}&76\cr
 \ct{1.00}{0.53}{0.00}{Stabilo red}& 208 & \ct{0.37}{0.53}{0.84}{Stabilo blue}    & 68\cr
 \ct{0.53}{0.00}{1.00}{Herbin Violette Pens\'ee}&  93 & \ct{0.37}{0.69}{1.00}{Staedtler blue}&75\cr
-\ct{0.37}{0.53}{0.00}{Herbin Vert Empire}&        64 &\cr
+\ct{0.37}{0.53}{0.00}{Herbin Vert Empire}&        64 & \omit & \omit \cr
 }
 
 \vfill