-Improved theme editor, when a new class is added, the members are created empty, closes #4619

-Made theme editor take less vertical space by using a scroll area

tools/editor/plugins/theme_editor_plugin.h

@@ -35,16 +35,19 @@
 #include "scene/gui/file_dialog.h"
 #include "scene/gui/check_box.h"
 #include "scene/gui/button_group.h"
+#include "scene/gui/scroll_container.h"
 
 #include "tools/editor/editor_node.h"
 
 
 
+
 class ThemeEditor : public Control {
 
 	OBJ_TYPE( ThemeEditor, Control );
 
 
+	ScrollContainer *scroll;
 	VBoxContainer *main_vb;
 	Ref<Theme> theme;