Add README.md and rendered image to many examples

The examples were found by

```bash
$ find . -mindepth 2 -maxdepth 2 -type d '!' -exec test -e "{}/README.md" ';' -print
```

uml/class-diagramm/Makefile

@@ -7,6 +7,10 @@ author		:= Martin Thoma
 version		:= 1.0
 
 DATE=$(shell date +%Y-%m-%d)
+SOURCE = class-diagram
+DELAY = 80
+DENSITY = 300
+WIDTH = 512
 
 make:
 	mpost meta.mp
@@ -15,3 +19,20 @@ make:
 
 clean:
 	rm -rf  $(TARGET) *.class *.html *.log *.aux *.out *.1
+
+png:
+	make
+	make svg
+	inkscape $(SOURCE).svg -w $(WIDTH) --export-png=$(SOURCE).png
+
+transparentGif:
+	convert $(SOURCE).pdf -transparent white result.gif
+	make clean
+
+svg:
+	#inkscape $(SOURCE).pdf --export-plain-svg=$(SOURCE).svg
+	pdf2svg $(SOURCE).pdf $(SOURCE).svg
+	# Necessary, as pdf2svg does not always create valid svgs:
+	inkscape $(SOURCE).svg --export-width=$(WIDTH) --export-plain-svg=$(SOURCE)1.svg
+	rsvg-convert -a -w 720 -f svg $(SOURCE)1.svg -o $(SOURCE).svg
+	rm $(SOURCE)1.svg

uml/class-diagramm/README.md

@@ -0,0 +1,3 @@
+Compiled example
+----------------
+![Example](class-diagram.png)