replaced outdated 'destroy's with 'dispose'

MainWindow.cs

@@ -64,11 +64,9 @@ namespace Buypeeb {
 			ed.ContentArea.PackStart(edEntry, true, true, 10);
 			edEntry.Show();
 
-			// TODO: pressing enter should submit the form
-
 			ResponseType accepted = (ResponseType)ed.Run();
 			string response = edEntry.Text;
-			ed.Destroy();
+			ed.Dispose();
 			return (accepted == ResponseType.Ok, response);
 		}
 
@@ -99,7 +97,7 @@ namespace Buypeeb {
 		private void ButtonQuitClicked(object sender, EventArgs a) {
 			MessageDialog md = new MessageDialog(null, DialogFlags.DestroyWithParent, MessageType.Question, ButtonsType.OkCancel, "Are you sure you want to quit?");
 			ResponseType response = (ResponseType)md.Run();
-			md.Destroy();
+			md.Dispose();
 			if (response == ResponseType.Ok) {
 				Application.Quit();
 			}