【Egret Engine】自適銀幕大小做法

修改launcher/egret_loader.js

   1: egret.StageDelegate.getInstance().setDesignSize(document.body.clientWidth, Math.max(document.body.clientHeight,window.innerHeight));

   2: context.stage = new egret.Stage();

   3: var scaleMode =  egret.MainContext.deviceType == egret.MainContext.DEVICE_MOBILE ? egret.StageScaleMode.SHOW_ALL : egret.StageScaleMode.NO_SCALE;

   4: context.stage.scaleMode = scaleMode;