aveFile, A NetCDF FVCOM-SWAVE wave forcing file

 EXAMPLE USAGE
    write_FVCOM_elevtide(Mobj, MJD, '/tmp/waves.nc, 'Shelf tides')

 Author(s):
    Pierre Cazenave (Plymouth Marine Laboratory)
    Karen Thurston (National Oceanography Centre Liverpool)
    DarrenPrice (based upon above authors)
 Revision history
    2012-08-08 (PWC) First version.
    2012-11-14 (PWC) Updated to expect Modified Julian Day rather than
    doing the conversion in here. Also put the pieces in set_elevtide in
    h