FXMLDemoFromSceneBuilderFile fails calling scene.lookup

[rich-coe]

Exception in Application start method Caught: java.lang.RuntimeException: Exception in Application start method java.lang.RuntimeException: Exception in Application start method at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917) at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182) Caused by: java.lang.NullPointerException: Cannot set property 'title' on null object at FXMLDemoFromSceneBuilderFile$_run_closure1.doCall(FXMLDemoFromSceneBuilderFile.groovy:30) at groovyx.javafx.GroovyFX.start(GroovyFX.java:40) at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863) at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326) at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295) at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294) at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method) at com.sun.glass.ui.gtk.GtkApplication.lambda$null$49(GtkApplication.java:139)

According to https://stackoverflow.com/questions/32773847/scene-lookup-returns-null-if-i-search-my-vbox lookups ''are not very robust"

[rich-coe]

pull request #58 fixes this issue