http://stackoverflow.com/questions/2694411/text-inset-for-uitextfieldmyTextField.layer.sublayerTransform = CATransform3DMakeTranslation(5, 0, 0);
占位符和输入的字符离边框的距离调整
ios-Text inset for UITextField
原文：http://www.cnblogs.com/qike/p/5404363.html
