Use GetEntryAssembly() to derive app_name

This fixes an issue where notify-sharp users (e.g. Banshee) which use one of
the Notification constructors that accept arguments end up sending an app_name
of "notify-sharp" to notification daemons, which causes issues between Banshee
and GNOME Shell where notifications are concerned. (bgo#656533 and lp#825769)

src/Notification.cs

@@ -112,7 +112,12 @@ private struct ActionTuple {
 			nf.NotificationClosed += OnClosed;
 			nf.ActionInvoked += OnActionInvoked;
 
-			this.app_name = Assembly.GetCallingAssembly().GetName().Name;
+			Assembly app_asm = Assembly.GetEntryAssembly();
+
+			if (app_asm == null)
+			    app_asm = Assembly.GetCallingAssembly();
+
+			this.app_name = app_asm.GetName().Name;
 		}
 
 		public Notification (string summary, string body) : this () {