CREATEHN Creates topology neighbourhood HN for topology H

 USAGE:

       HN = createHN(H)

 DESCRIPTION:

       This can function can be used to create a neighborhood
       matrix for a given element topology

 INPUT:

       H           - Element topology

 OPTIONAL INPUT:

       optarg1     - Description of the first optional argument [J/m3]

 OUTPUT:

       HN          - Neighborhood topology

 This function is provided with ValoMC