confirm payed order.
test ability.
add admin orders controller test.
show payment method in notify mail.
add order pay_with_bank_transfer method.
show invoice title.
change labels.
highlight invoice title.
improve usable
Merge pull request #572 from jasl/order-stats

improve usable
add Ransack gem for search.
add ransack predicate.
search orders depends on ticket and price.
show submit refund form.
let it can run in version 1.9.3 because `%i()` is not compatible
add paid amount and refunded amount to order.
add event order refund model.
config state from event order refund.
add event order refund observer.
add event order refund model test.