renamed src/2d/shallow/fgmax_interpolate1.f90 -> src/2d/shallow/fgmax_interpolate.f90 and changed Makefiles back from fgmax_interpolate0.f90 to fgmax_interpolate.f90 ...
for backward compatibility -- users will not have to change Makefiles in existing apps and bilinear interpolation will be done as before (with some bug fixes). Need to add documentation suggesting fgmax_interpolate0.f90 may be a better choice.