Removed dprev array, which is no longer needed.   The displacement increments are now copied directly from deld into dispvec at the end of a time step.  Added call at the end of the solution to accomplish this by calling idisp.
Removed dprev array, which is no longer needed.   The displacement
increments are now copied directly from deld into dispvec at the end
of a time step.  Added call at the end of the solution to accomplish
this by calling idisp.


geodynamics/lithomop,geodynamics/lithomop,geodynamics/lithomop,geodynamics/lithomop