Fix destroy signal.

src/MainWindow.vala

@@ -40,6 +40,8 @@ namespace LAview.Desktop {
 			application.app_menu = builder.get_object ("menubar") as MenuModel;
 			application.menubar = builder.get_object ("main_toolbar") as MenuModel;
 			window.application = application;
+
+			window.destroy.connect (() => { window.application.quit (); });
 		}
 
 		void fill_liststore_templates () {

ui/glade/laview-desktop.glade

@@ -395,7 +395,6 @@
     <property name="margin_top">3</property>
     <property name="border_width">4</property>
     <property name="title" translatable="yes">LAview Desktop</property>
-    <signal name="destroy" handler="gtk_main_quit" swapped="no"/>
     <child>
       <object class="GtkBox" id="main_vbox">
         <property name="visible">True</property>