Memory leak sometimes when UIScrollView is released. 在cap app里,有时在dimmer layer or menu panel进行手势动作时,就会memory leak about "strdup". it is ios bug!
参看
https://devforums.apple.com/message/630695
http://stackoverflow.com/questions/9762995/memory-leak-every-time-uiscrollview-is-released
http://stackoverflow.com/questions/9880336/obj-c-memory-leak-of-malloc-48-bytes-in-strdup-frame