http://insideria.com/2010/10/an-introduction-to-as3-signals.html
睇左先
up 一大春英文，搞咩，超簡單
signal 係可以 pass parameter，但 pass 個個 object 就係個個 object 囉

DeluxeSignal 就勁啦，係 pass event
event signal 都識 pass 啦，咁你就錯
呢個 event 係 as3 d fd，你 pass 左，過到去，有翻曬你以前 event 玩既野
例如 event.currentTaret, event.type, event.target 咁
咁咪開心又興奮囉~