removing poster feature
Monnand <monnand@gmail.com>

Step 1: GetOrDel -> GetThenDel
Step 2: Deleted poster related test cases
removing poster feature
Monnand <monnand@gmail.com>

Step 3: Removing SetPoster() and PosterId()
removing poster feature

Step 4: 'SetMail->CacheMessage'
Step 5: misc
removing poster feature
Nan Deng <monnand@gmail.com>

Step 7: changing/removing functions respectively
removing poster feature.
Nan Deng <monnand@gmail.com>

Step 8: Passed all test cases.