Initial revision of utility to fit a much reduced size terrain surface

to a higher res data set, attempting to preserve the most important
features in the original data set.  The user can specify a min and max
number of output nodes as well as a maximum error tolerance that should
not be exceeded (between the original and simplified surfaces.)

src/Prep/ArrayFit/arrayfit.cxx

@@ -186,7 +186,7 @@ int main( int argc, char **argv ) {
             } else {
                 x = basex + i * dx;
                 y = basey + j * dy;
-                z = a.get_point( i, j );
+                z = a.get_array_elev( i, j );
                 pending.push_back( Point3D(x, y, z) );
             }
         }