Implemented monitor (dis)connect callback for win32.

src/win32_window.c

@@ -30,7 +30,6 @@
 
 #include "internal.h"
 
-#include <stdio.h>
 #include <stdlib.h>
 
 
@@ -1104,6 +1103,16 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
 
             break;
         }
+
+        case WM_DEVICECHANGE:
+        {
+            if (DBT_DEVNODES_CHANGED == wParam)
+            {
+                _glfwRefreshMonitors();
+                return TRUE;
+            }
+            break;
+        }
     }
 
     // Pass all unhandled messages to DefWindowProc