BaseEntity缺省的public String getDisplay() 实现定义

Signed-off-by: lixia <xautlx@hotmail.com>
优化分组聚合的实现，并新增支持as别名语法

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改进Grid日期类型属性的查询支持，基于区间段选取查询

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README添加主子表图展示

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