获取到的'translatPoint':
1)有方向(分正负)
2)取值是相对于'自身原点(0,0)'(自己左上角的点)移动了多少
CGPoint translatPoint = [pan translationInView:self.view]
2016-11-23 16:48:43.022 WXSideMenuExample[25268:5860659] 27.000000 0.000000
2016-11-23 16:48:43.206 WXSideMenuExample[25268:5860659] 39.000000 4.000000
2016-11-23 16:49:43.682 WXSideMenuExample[25268:5860659] -16.000000 14.000000
2016-11-23 16:49:43.766 WXSideMenuExample[25268:5860659] -16.500000 14.000000
获取到的'localPoint':
1)无方向
2)取值是 手指tap的那个'点'，在self.view的位置坐标；
CGPoint localPoint = [pan locationInView:self.view];
2016-11-23 16:49:43.683 WXSideMenuExample[25268:5860659] 205.500000 465.500000
2016-11-23 16:49:43.767 WXSideMenuExample[25268:5860659] 205.000000 465.500000
2016-11-23 16:49:43.817 WXSideMenuExample[25268:5860659] 204.500000 465.500000
2016-11-23 16:49:43.865 WXSideMenuExample[25268:5860659] 204.000000 466.000000
获取到的'velocityPoint':
1)有方向
2)取值是 速度；
CGPoint velocityPoint = [recognizer velocityInView:self.view]
以上两个，一个是移动量的体现，一个是相对view的位置
