Fixed link to TestNiftyToMesh.java

src/docs/asciidoc/jme3/advanced/nifty_gui_projection.adoc

@@ -27,7 +27,7 @@ This +++<abbr title="Graphical User Interface">GUI</abbr>+++ projection variant
 
 == Sample Code
 
-*  link:http://code.google.com/p/jmonkeyengine/source/browse/trunk/engine/src/test/jme3test/niftygui/TestNiftyToMesh.java[TestNiftyToMesh.java]
+*  link:https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-examples/src/main/java/jme3test/niftygui/TestNiftyToMesh.java[TestNiftyToMesh.java]
 
 
 == Projecting the User Interface Onto a Texture