rfb_win32: Add support for LED state notifications

LED support added using Windows GetKeyState() API call.

The state is polled for change in CapsLock/NumLock/ScrollLock
status in the same code block where chages to Cursor shape is polled.

Signed-off-by: Rahul Kale <Rahul.Kale@barco.com>
Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com>
diff --git a/win/rfb_win32/SDisplay.h b/win/rfb_win32/SDisplay.h
index b021782..e43e302 100644
--- a/win/rfb_win32/SDisplay.h
+++ b/win/rfb_win32/SDisplay.h
@@ -106,6 +106,7 @@
       void restartCore();
       void recreatePixelBuffer(bool force=false);
       bool flushChangeTracker();  // true if flushed, false if empty
+      bool checkLedState();
 
       VNCServer* server;
 
@@ -151,6 +152,8 @@
 
       // -=- Where to write the active/inactive indicator to
       bool* statusLocation;
+
+      unsigned ledState;
     };
 
   }