Description 
LineCurvature2D, This function calculates the curvature of a 2D line. It first fits polygons to the points. Then calculates the analytical curvature from the polygons.
K = LineCurvature2D(Vertices,Lines)
inputs,
Vertices : A M x 2 list of line points.
(optional)
Lines : A N x 2 list of line pieces, by indices of the vertices
(if not set assume Lines=[1 2; 3 4 ; ... ; M1 M])
outputs,
K : M x 1 Curvature values
.
.
LineNormals2D, This function calculates the normals, of the line. Using the neighbouring points of each line/contour point, and forward an backward differences on the end points
N=LineNormals2D(V,L)
inputs,
V : List of points/vertices 2 x M
(optional)
Lines : A N x 2 list of line pieces, by indices of the vertices
(if not set assume Lines=[1 2; 3 4 ; ... ; M1 M])
outputs,
N : The normals of the Vertices 2 x M
