Distance between a point and a triangle in 3D

Calculate the distance of a given point P from a triangle TRI.
Point P is a row vector of the form 1x3. The triangle is a matrix
formed by three rows of points TRI = [P1;P2;P3] each of size 1x3.
dist = pointTriangleDistance(TRI,P) returns the distance of the point P to the triangle TRI.
[dist,PP0] = pointTriangleDistance(TRI,P) additionally returns the closest point PP0 to P on the triangle TRI.