"Pull down to refresh" Table view

http://stackoverflow.com/questions/3535827/is-there-a-interface-builder-esque-way-to-get-that-slick-pull-down-to-refresh-m

http://blog.jcmultimedia.com.au/2010/07/pull-down-refresh.html

https://github.com/enormego/EGOTableViewPullRefresh

http://www.waterworld.com.hk/zh-hant/blog/pull-down-refresh-table-view

http://www.cocoanetics.com/2009/12/how-to-make-a-pull-to-reload-tableview-just-like-tweetie-2/