== DESCRIPTION: Inspired by EGOTableViewPullRefresh[https://github.com/enormego/EGOTableViewPullRefresh], a similar control to the pull down to refresh control created by atebits in Tweetie 2, I implement this simple control to load more rows into the table. == Usage: Check the demo. Thanks for enormego. Most of the codes are directly copied from their demo. == LICENSE: Copyright (c) 2010 Dingding Ye and Intridea, Inc. ( http://intridea.com ), released under the MIT License.