Increase duplicate clipboard update treshhold

The windows screenshot app issues two consecutive updates of clipboard data within some 50 to 400 ms. In batch mode we ignore the second update.

Author: eltos

PasteIntoFile/Dialog.cs

@@ -223,7 +223,7 @@ private void ClipboardChanged(Object sender, SharpClipboard.ClipboardChangedEven
             if (Settings.Default.continuousMode) {
                 var ignore = false;
                 // ignore duplicate updates within 100ms
-                ignore |= (clipData.Timestamp - previousClipboardTimestamp).TotalMilliseconds <= 100;
+                ignore |= (clipData.Timestamp - previousClipboardTimestamp).TotalMilliseconds <= 500;
                 // ignore internal updates due to clipboard patching
                 ignore |= Clipboard.ContainsData(Program.PATCHED_CLIPBOARD_MAGIC);