Add colormaps to documentation.

Former-commit-id: d9db76c4f0715800ef6f94e6618d6682a2c8112b

docs/gen_doc_gifs.sh

@@ -1,11 +1,17 @@
 #!/usr/bin/env bash
 ROOT=`stack path --project-root`
 
+TINY='^(doc_turbo|doc_viridis|doc_magma|doc_inferno|doc_plasma|doc_sinebow|doc_cividis|doc_jet|doc_hsv|doc_hsvMatlab|doc_greyscale|doc_parula)$'
+
 for src in $ROOT/examples/doc_*.hs; do
   BASE=`basename $src .hs`
   DST=$ROOT/docs/gifs/$BASE.gif
   if [[ "$src" -nt "$DST" ]]; then
     echo stack $src render -o $DST
-    stack $src render -o $DST
+    if [[ "$BASE" =~ $TINY ]]; then
+      stack $src render -o $DST --width=320 --height=50
+    else
+      stack $src render -o $DST
+    fi
   fi
 done