 ncomp is set by number of sources components, "n2"
 that is true for all.

 
 pressure source by principal stresses
 shear source  done by double couple


recent change  seismo -> ngroup itr1


Feb 1994
allowed dtseis != dt,
needs change in all timestep*.rcm, only did timestepN.rcm.


Feb 1994
move division by rho to later point after adding in the forces.
test if reciprocal
