http://www.appcoda.com/introduction-auto-layout/?hc_location=ufi
https://www.youtube.com/watch?v=G53PuA_TlXk&hc_location=ufi
http://monkey-oyster.blogspot.tw/2014/10/auto-layout.html?hc_location=ufi
http://mywayonobjectivec.blogspot.tw/2014/11/viewcontrollerautolayout.html?hc_location=ufi
