a.d.rasinski   december 1964   subroutine numint
main program for nordsieck integration of n first order
ordinary differential equations with modifications
such that only the first m equations will control the
interval size.  branch for corout,fn added oct 67, nov 69.
timer added aug 1967
forward-backward added december 1967

ngo=1 planet-asteroid integration (obsolete)
ngo=2 moon integration (obsolete)
ngo=3 satellite-probe integration (numint called by planet)
ngo=4 n-body integration (numint called by planet)
ngo=5 earth rotation integration
ngo=6 moon rotation integration (obsolete)
ngo=7 planet rotation integration
ngo=8 moon orbit and rotation integration