Make the script better readable

Signed-off-by: Joas Schilling <coding@schilljs.com>

build/image-optimization.sh

 #!/usr/bin/env bash
 
 function recursive_optimize_images() {
-cd $1;
-optipng -o6 -strip all *.png;
-jpegoptim --strip-all *.jpg;
-for svg in `ls *.svg`;
-do
-    mv $svg $svg.opttmp;
-    scour --create-groups --enable-id-stripping --enable-comment-stripping --shorten-ids --remove-metadata --strip-xml-prolog --no-line-breaks  -i $svg.opttmp -o $svg;
-done;
-rm *.opttmp
-for dir in `ls -d */`;
-do
-    recursive_optimize_images $dir;
-    cd ..;
-done;
+	cd "$1":
+
+	# Optimize all JPGs and PNGs
+	optipng -o6 -strip all *.png;
+	jpegoptim --strip-all *.jpg;
+
+	# Optimize all SVGs
+	for svg in `ls *.svg`;
+	do
+		mv $svg $svg.opttmp;
+		scour --create-groups \
+			--enable-id-stripping \
+			--enable-comment-stripping \
+			--shorten-ids \
+			--remove-metadata \
+			--strip-xml-prolog \
+			--no-line-breaks  \
+			-i $svg.opttmp \
+			-o $svg;
+	done;
+
+	# Remove temporary SVGs
+	rm *.opttmp
+
+	# Check all subfolders
+	for dir in `ls -d */`;
+	do
+			recursive_optimize_images $dir;
+			cd ..;
+	done;
 }
 
 recursive_optimize_images ../