add event order item unit price.
use order item unit price to search order instead of total price.
fixed rspec error.
fixed: unit price don't show.
Merge pull request #583 from saberma/saberma-enhancement/add-order-item-unit_price

修正订单查询单价结果不正确的问题
fixed unit price is zero after db migration.
Merge pull request #584 from saberma/saberma-enhancement/add-order-item-unit_price

修正迁徙后订单门票单价未初始化的问题
show refund reason in email.
fixed finished event cancel! error when alipay notify.
Merge pull request #585 from saberma/saberma-enhancement/579-show-refund-reason-in-email

退款通知邮件中要显示退款原因