Support combination of Ctrl, Alt and Shift for setCtrlKeys API

<zk>
	<zscript><![CDATA[
	void doSomething(int keyCode) {
		System.out.println(keyCode);
	}
	]]></zscript>
	<window ctrlKeys="@^t" onCtrlKey="doSomething(event.getKeyCode())">
		<textbox />
	</window>
</zk>