copied from Mark 15.may.1996,
just a beta version, not fully tested

03/11/00 (jh) - re-written I/O operations, several bug fixes
including 3D topo parameters, and 2nd RST derivatives

12/07/00 (MN) - added field selection parameter for sites lists  
                (allows to select column in site_lists)

02/03/03 (jh) - added deviation site file to the output