[Add]添加VtBarData的K线周期字段
[Add]添加VtBarData的K线周期字段

msincenselee/vnpy,bigdig/vnpy,bigdig/vnpy,andrewchenshx/vnpy,andrewchenshx/vnpy,andrewchenshx/vnpy,vnpy/vnpy,vnpy/vnpy,bigdig/vnpy,andrewchenshx/vnpy,msincenselee/vnpy,msincenselee/vnpy,bigdig/vnpy,msincenselee/vnpy,andrewchenshx/vnpy