Added link to 3-d rotation.

src/docs/asciidoc/jme3.adoc

@@ -94,6 +94,7 @@ Now that you understood the basics, let's put it all together. The following int
 *  <<jme3/math_for_dummies#,jME3 Math for Dummies>>
 *  <<jme3/intermediate/math#,Short 3D math &quot;cheat sheet&quot;>>
 *  <<jme3/math#,jME3 math overview>>
+*  <<jme3/rotate#,3-D Rotation>>
 *  <<jme3/math_video_tutorials#,Videos: jME3 math video tutorial series>>
 
 === 3D Graphics Concepts