Handle Ctrl+Alt+Delete in raw keyboard mode

Ctrl+Alt+Delete requires special handling to trigger on Windows.
Make sure this works in raw keyboard mode as well.
diff --git a/win/rfb_win32/SInput.cxx b/win/rfb_win32/SInput.cxx
index e6da9b8..d41e14b 100644
--- a/win/rfb_win32/SInput.cxx
+++ b/win/rfb_win32/SInput.cxx
@@ -377,6 +377,14 @@
     if ((keycode == 0x54) && !(GetAsyncKeyState(VK_MENU) & 0x8000))
       keycode = 0xb7;
 
+    if (down && (keycode == 0xd3) &&
+        ((GetAsyncKeyState(VK_CONTROL) & 0x8000) != 0) &&
+        ((GetAsyncKeyState(VK_MENU) & 0x8000) != 0))
+    {
+      rfb::win32::emulateCtrlAltDel();
+      return;
+    }
+
     doScanCodeEvent(keycode, down);
     return;
   }