fixed container is Array & container[0] is hidden Ele

bug场景如：http://jsfiddle.net/stu2006/VtFs7/2/
container的setter使用了return DOM.get(x)，导致当container为数组时取第一个元素，

        container: {
            setter: function (el) {
                el = el || doc;
                if (S.isWindow(el)) {
                    el = el.document;
                } else {
                    el = DOM.get(el);
                    if (DOM.nodeName(el) == 'body') {
                        el = el.ownerDocument;
                    }
                }
                return el;
            },
          

container[0]是offsetWidth==0状态时，原container所有节点都被中止检测，导致lazyload失败

            if (self._containerIsNotDocument && !container.offsetWidth) {
                return;
            }

解决办法有多种，按_filterItems中兼容1.2的处理办法感觉是最简单的，所以在_loadItems中也使用了这种方式处理，1.3.0 、1.3.2中测试通过

            S.each(containers,function(container){
                // container is display none
                if (self._containerIsNotDocument && !container.offsetWidth) {
                    return;
                }
                windowRegion = self['_getBoundingRect']();
                // 兼容，不检测 container
                if (!self._backCompact && self._containerIsNotDocument) {
                    containerRegion = self['_getBoundingRect'](self.get('container'));
                }
                self['_loadImgs'](windowRegion, containerRegion);
                self['_loadTextAreas'](windowRegion, containerRegion);
                self['_fireCallbacks'](windowRegion, containerRegion);
            });