修改表结构及相应代码：account_cost_info删除num字段-lyx
Merge remote-tracking branch 'origin/master'
程序自动关闭问题消失，恢复祥子的代码-lyx
account_cost_bill表删除num字段-lyx
Merge remote-tracking branch 'origin/master'

Conflicts:
	roommgr/ui/main_window.py