Alipay

- Remove Alipay.seller_email setting, it can be replaced by seller_id, than same with pid.
- Alipay::Wap::Service.trade_create_direct_token add a required params: seller_account_name.

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- add `send_goods_confirm_by_platform` method

New API:

- Add Alipay::Service.mobile_security_pay_url.
- All service methods accept `options` args to config pid, seller_email and key.

New Config:

- Add `Alipay.sign_type`, default is 'MD5', allow: 'MD5', 'RSA'. 'DSA' is not implemented yet.

Break Changes:

- Move `Alipay::Service::Wap` to `Alipay::Wap::Service`
- Move `Alipay::Sign::Wap` to `Alipay::Wap::Sign`
- Move `Alipay::Notify::Wap` to `Alipay::Wap::Notify`
- Rename `Alipay::Service.create_forex_single_refund_url` to `Alipay::Service.forex_refund_url`
- Rename `Alipay::Service.create_forex_trade` to `Alipay::Service.create_forex_trade_url`
- Rename `Alipay::Service.create_refund_url` to `Alipay::Service.refund_fastpay_by_platform_pwd_url`
- Rename `Service::Wap.auth_and_execute` to `Service::Wap::Service.auth_and_execute_url`

Now `Alipay::Sign.verify?` and `Alipay::Wap::Sign.verify?` detect sign_type by params.

Development:

- Update Test::Unit to Minitest.
- Use fxied test data.

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- add `add_alipay_qrcode` method

- Add `forex_single_refund` service.
- Add `debug_mode` config:

set `Alipay.debug_mode = false` to disable options check warning in production env.

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- Fix argument type error of verify_notify in README

- FIX SEVERE FAULT IN `check_notify_remotely`