Fix bug of encryption (check mac value) when some fields are not used.
Dynamically sort existing fields and connect them to string.
Merge pull request #1 from lulalala/encrypt_data

Fix bug of encryption (check mac value) when some fields are not used.
Fix bug

Fix bug of encryption (check mac value) when some fields are not used.
Fix bug - 修復 notification check sum 檢查問題, 先 sort params by hash key
Merge pull request #3 from afunction/master

Fix bug - 修復 notification check sum 檢查問題, 先 sort params by hash key

according Allpay document, all params need to be sorted.
Bump to 0.1.3

a. Fix bug - 修復 notification check sum 檢查問題, 先 sort params by hash key
Setup test environment.
`rake test` to run.
Use stripped version of test_helper.
Install test-unit gem because Ruby 2.0 only have
minutest.
Follow standard interface and consume raw_post
instead of params from Rails.
父類別與其他實作都是接受 raw_post，所以遵循此介面。
父類別也有定義 params 變數跟其 parse 實作，可直接使用。
Merge pull request #4 from lulalala/test_env

Setup test environment.
Merge pull request #5 from lulalala/use_raw_post

Use raw post