Add taskVector, which include all task in history.
Enable refresh taskTable,and make only one time refresh when
multi refresh task is called
Add some data to ShellCommand.Fix the lost of refreshTable(true).
Add popupMenuItems to popupMenu.
Add the forgotten APopupMenu.
现在可以显示百分比，速度，每隔0.5s会刷新一次任务栏。但是有的时候下载会卡住，不知道为什么，对比过bypy，bypy也会出现这种情况，重新打开BYA可能可以继续下载。