Fix SOMA and ZISO script links

[xylar]

There are two testcases that use links to testing_and_setup/compass using mpas_model as the base. This was never the intended way of finding contents of testcases, and no longer works now that COMPASS is in its own repo. These two links have been fixed in this merge.

partially addresses #20

[xylar]

@mark-petersen, will this be easy for you to test?

[xylar]

Testing

I didn't actually try to run these tests but the links are now correct:

xylar@burnham:~/data/mpas/test_soma_ziso/ocean/ziso/20km/default/forward$ ls -lah
...
lrwxrwxrwx 1 xylar xylar  105 Nov 10 15:05 make_particles.py -> /home/xylar/code/mpas-work/compass/fix_soma_ziso_links/ocean/scripts/LIGHTparticles/make_particle_file.py

and

xylar@burnham:~/data/mpas/test_soma_ziso/ocean/soma/32km/default/analysis$ ls -lah
...
lrwxrwxrwx 1 xylar xylar  101 Nov 10 15:05 check_particle_sampling.py -> /home/xylar/code/mpas-work/compass/fix_soma_ziso_links/ocean/soma/analysis/check_particle_sampling.py

[mark-petersen]

Ran nightly test suite, with compiled MPAS-O within the compass subdirectory. Worked great. thanks.

[xylar]

Thanks, @mark-petersen!