added example to readme

tikz/3d-vector/Readme.md

@@ -1,3 +1,8 @@
 Manual
 ------
 [TikZ - 3d plot](http://sunsite.informatik.rwth-aachen.de/ftp/pub/mirror/ctan/graphics/pgf/contrib/tikz-3dplot/tikz-3dplot_documentation.pdf)
+
+
+Compiled example
+----------------
+![An example for the package tikz-3dplot](3d-vector.png "An example for the package tikz-3dplot")