WIP: basic availability of LayoutView as separate component

- The deferred method scheduler is now automatically created
  when required and when there is a QApplication
- QApplication and related have argv constructors

src/laybasic/laybasic/gsiDeclLayLayoutView.cc

@@ -23,6 +23,8 @@
 
 #include "gsiDecl.h"
 #include "gsiSignals.h"
+#include "gsiQtGuiExternals.h"
+#include "gsiQtWidgetsExternals.h"  // for Qt5
 #include "rdb.h"
 #include "layLayoutView.h"
 #include "layDitherPattern.h"
@@ -367,7 +369,7 @@ static lay::LayoutView *new_view ()
   return new lay::LayoutView (0, false, 0);
 }
 
-Class<lay::LayoutView> decl_LayoutView ("lay", "LayoutView",
+Class<lay::LayoutView> decl_LayoutView (QT_EXTERNAL_BASE (QWidget) "lay", "LayoutView",
   gsi::constructor ("new", &new_view,
     "@brief Creates a standalone view\n"
     "\n"

src/laybasic/laybasic/layLayoutView.cc

@@ -255,6 +255,9 @@ LayoutView::LayoutView (db::Manager *manager, bool editable, lay::PluginRoot *ro
     m_annotation_shapes (manager),
     dm_prop_changed (this, &LayoutView::do_prop_changed) 
 {
+  //  ensures the deferred method scheduler is present
+  tl::DeferredMethodScheduler::instance ();
+
   setObjectName (QString::fromUtf8 (name));
   init (manager, root, parent);
 }
@@ -267,6 +270,9 @@ LayoutView::LayoutView (lay::LayoutView *source, db::Manager *manager, bool edit
     m_annotation_shapes (manager),
     dm_prop_changed (this, &LayoutView::do_prop_changed)
 {
+  //  ensures the deferred method scheduler is present
+  tl::DeferredMethodScheduler::instance ();
+
   setObjectName (QString::fromUtf8 (name));
 
   m_annotation_shapes = source->m_annotation_shapes;