Keyboard Handling [5/8]: Update rfb.js to connect mouse events to keyboard handler

This allows the keyboard handler to check modifier key state much more frequently

Since some browsers never send keyup events for modifier keys, we have to
synchronize modifier state whenever we get a mouse or keyboard event

include/rfb.js

@@ -223,7 +223,8 @@ function constructor() {
                                 'onKeyPress': keyPress});
     mouse    = new Mouse({'target': conf.target,
                             'onMouseButton': mouseButton,
-                            'onMouseMove': mouseMove});
+                            'onMouseMove': mouseMove,
+                            'notify': keyboard.sync});
 
     rmode = display.get_render_mode();