Added link to the future of simpleapplication topic in the begginer tutorials.

src/docs/asciidoc/jme3/intermediate/simpleapplication.adoc

@@ -18,6 +18,7 @@ SimpleApplication gives you access to standard game features, such as a scene gr
 For each game, you (directly or indirectly) extend SimpleApplication exactly once as the central class. If you need access to any SimpleApplication features from another game class, make the other class extend <<jme3/advanced/application_states#,AbstractAppState>> (don't extend SimpleApplication once more).
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+NOTE: The SimpleApplication class is undergoing changes. To understand how these changes may affect your projects and how to best prepare for them, see  <<jme3/beginner/hello_simpleapplication#the-future-of-simpleapplication#,The Future of SimpleApplication>> topic in the "`Hello SimpleApplication`" tutorial for beginners.
 
 The following code sample shows the typical base structure of a jME3 game: