FSPageContentView和系统侧滑返回手势冲突解决

1.将pageContentView的collectionView属性生成放在.h里面，可以对外调用

2.手势判断滑动到屏幕边缘时，把pageContentView.collectionView的手势禁掉。代码如下

    for (UIGestureRecognizer *gesture in self.navigationController.view.gestureRecognizers) {

        if ([gesture isKindOfClass:[UIScreenEdgePanGestureRecognizer class]]){

            [self.pageContentView.collectionView.panGestureRecognizer requireGestureRecognizerToFail:gesture];

        }

    }