Update Fortran so FMS is built with -DGFS_PHYS

[oliverwm1]

This has the effect of changing the physical constants used by fv3gfs and thus required a change to the md5sum files in fv3gfs-fortran.

[mcgibbon]

There are a couple different changes bundled here, make sure you've tested regression in fv3gfs-fortran on all the changes apart from the changing of physical constants, and applied the physical constants update separately. I'm just trusting you've done that already in that repo (so it's fine to bundle them here).

May want to also add the corresponding entry for the new 0.3.x version.

[oliverwm1]

There are a couple different changes bundled here, make sure you've tested regression in fv3gfs-fortran on all the changes apart from the changing of physical constants, and applied the physical constants update separately. I'm just trusting you've done that already in that repo (so it's fine to bundle them here).

Yes good point. Indeed in the fv3gfs-fortran PR, I made the physical constants change apart from anything else, and confirmed that that was the change that required a modification of the regression test data. But since that commit came after the coarse-graining code, it's easiest to bundle them together for this PR to fv3gfs-python.

[oliverwm1]

May want to also add the corresponding entry for the new 0.3.x version.

I'll do this in #62