daily bug fix

bug1: 相关问题，相关文章显示列表，若结果集为空，sql语句执行错误
cause： SqlDataReader reader = DbHelper.ExecuteReader(
String.Format("SELECT QuestionTagAssociation.* FROM [Question],[QuestionTagAssociation] WHERE Question.qid=QuestionTagAssociation.qid and tid in(" + b + ")"
),conn
b可能为空
fix: if(b=="")return

bug2: List.aspx,选择排序规则后一直显示载入问题
cause：
function changeMode()
{
var type = $("#TypeList").val();
var orderType = $("#OrderTypeList").val();
load(tagId,type,orderType,pageNum);
}
fix: 删除 var type = $("#TypeList").val();