Revert "add CommentDAO,Unittest successful AddCompareDAO,UNITTEST,there is a problem on arraylist"

This reverts commit 034466979c0fc305ed0376e2d01dcb2766086fab.
Revert "policyDAO and CompareDAO"

This reverts commit ecea1e0645ba396d6c940d0ac11daba83b78f742.
CommentDAO, and CompareDAO -- Writen by Weiqi
finished promote and get comments in Promote page. Fixed some GUI issue
on page promote. search compare or add new compare before go to Promote
page.
Weiqi's test