EXPORTMMC Export the mesh for mesh-based Monte Carlo (MMC) software suite

 DESCRIPTION:

       Exports the mesh for mesh-based Monte Carlo by Fang et
       al.

 NOTE:

       This is a simple wrapper but could be extended in the future to
       export also the optical coefficients if there is a need for such
       functionality

 USAGE:

       exportMMC(vmcmesh, vmcmedium, mmc_suffix)
       exportMMC(vmcmesh, vmcmedium, 'mymesh')

 INPUT:

       vmcmesh        - mesh structure for ValoMC
       vmcmedium      - medium for ValoMC
       mmc_suffix     - prefix to be used in MMC, e.g. node_{prefix}.dat

 This function provided with ValoMC