Another correction to the surface tracer 4DVAR adjustment

[arango]

The adjustment of surface tracer was corrected to include the various options available for heat and fresh water flux corrections. Also the forcing arrays need to clean during the convolutions in the W4DPSAS and W4DVAR algorithms.

Many thanks to Andy Moore for finding and fixing these problems. It amazing how technically complex are these algorithms. We keep fixing them. The good news is that we having very good results and convergence between strong and weak constraint algorithms.