ThreePointFitCircle

代码说明：

  给定三点坐标（二维），得到圆的圆心及坐标，并在matlab中坐图画出圆，并在图中标注原有圆的位置(Given three coordinates (2 d), get the round circle and coordinates, and sit in the matlab picture out of the circle, and mark the location of the original circle in the picture)