Added link to forum post on LWJGL v2 versus v3.

src/docs/asciidoc/jme3/requirements.adoc

@@ -33,6 +33,8 @@ Mac OS, only OpenGL 3.2 is available; You need to specify OpenGL 3.2 in AppSetti
 All platforms: +
 If you use the  LWJGL3 library (LWJGL2 is default), you need a specific launch argument (-XstartOnFirstThread), and thus can’t use any launchers not using the main thread. Because of this, calls to app.start() hang as it uses the current thread.
 
+See the forum post link:https://hub.jmonkeyengine.org/t/lwjgl-v2-versus-v3/42125[LWJGL v2 versus v3] for details.
+
 
 a|Java Development Kit
 a|JDK 7 or higher +