Updated the BasicGameTemplate to silence the project upgrader. Signalize that we are already on 3.1

BasicGameTemplate/nbproject/project.properties

@@ -66,6 +66,7 @@ javadoc.use=true
 javadoc.version=false
 javadoc.windowtitle=
 jaxbwiz.endorsed.dirs="${netbeans.home}/../ide12/modules/ext/jaxb/api"
+jme.project.version=3.1
 jnlp.codebase.type=local
 jnlp.descriptor=application
 jnlp.enabled=false