Add dead key support by exposing the "unknown" key

src/modules/keyboard/Keyboard.h

@@ -1,14 +1,14 @@
 /**
 * Copyright (c) 2006-2011 LOVE Development Team
-* 
+*
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
-* 
+*
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
-* 
+*
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
@@ -197,4 +197,4 @@ namespace keyboard
 } // keyboard
 } // love
 
-#endif // LOVE_KEYBOARD_KEYBOARD_H
+#endif // LOVE_KEYBOARD_KEYBOARD_H