Workaround for bug of CTRunDelegateRef and CTFramesetterRef on iOS 5/6.
Workaround for bug of CTRunDelegateRef and CTFramesetterRef on iOS 5/6.

HarrisLee/SECoreTextView,ywzw2013/SECoreTextView,yingzhuo1314/SECoreTextView,xiaonan0527/SECoreTextView,kishikawakatsumi/SECoreTextView,randyeasy/SECoreTextView,qskycolor/SECoreTextView