Markowitz Efficient Frontier

Calculates the Markowitz Efficient Frontier

This function calculates the coordinates of NumPoints-1 equally spaced points and those of the minimum variance portfolio of Markowitz efficient frontier.
If LongOnly is specified to be true then the frontier will be a long only constrained one. Risk is mesured by the std. deviation.
Returns a structure with members Return and Risk

Example:
LongOnlyFrontier=EfficientFrontier(Assets,100,1);
UnconstrainedFrontier=EfficientFrontier(Assets,100);