Modified Hausdorff Distance

This function computes the Modified Hausdorff Distance (MHD) which is
proven to function better than the directed HD as per Dubuisson et al.
in the following work:

M. P. Dubuisson and A. K. Jain. A Modified Hausdorff distance for object
matching. In ICPR94, pages A:566-568, Jerusalem, Israel, 1994.
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=576361

The function computed the forward and reverse distances and outputs the
minimum of both.

Format for calling function:

MHD = ModHausdorffDist(A,B);

where
MHD = Modified Hausdorff Distance.
A -> Point set 1
B -> Point set 2

No. of samples of each point set may be different but the dimension of
the points must be the same.