Max and Min of n-dimensional Matrices

Determines the max / min value and its index position of an n-dimensional matrix

Determines the minimum / maximum value and its index of an n-dimensional
matrix. E.g., for a 2D-Matrix x and y position of the min / max value are
returned, for a 3D-Matrix x, y and z position of min / max value are returned.

Syntax: [v,idx] = minN(A) / [v,idx] = minN(A)

Inputs:
A - the matrix of which the minimum / maximum value shall be found

Outputs:
v - the minimum / maximum value of A
idx - the index of v in matrix A

Example:
A(:,:,1) = [1,1,2;1,1,1;1,1,1];
A(:,:,2) = [1,1,1;1,1,1;1,1,1];
A(:,:,3) = [1,1,1;1,1,1;0,1,1];

[v1,idx1] = minN(A);
[v2,idx2] = maxN(A);

% v1 = 0, and idx1 = [3,1,3]
% v2 = 2, and idx2 = [1,3,1]
% it is A(3,1,3) = 0
% it is A(1,3,1) = 2