YISwipeShiftCaretios交互控件

适用于iOS的滑动到移动文本输入插入符号（无私有API）

示例代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // add swipe-shift-caret gestures to all of UITextField/UITextView
    [YISwipeShiftCaret install];

    //
    // or, you can implement gestures manually as follows, adding to non-textInput (wider parent) view:
    //
    // YISwipeShiftCaretGestureRecognizer* gesture = [[YISwipeShiftCaretGestureRecognizer alloc] initWithTextInput:self.textField];
    // [self.window addGestureRecognizer:gesture];

    return YES;
}