TODO list for tests

[yxqd]

• add a step of verification to san2d_grid test
• bring back tests temporarily disabled in test_ms_UN.py and test_ss_UN.py
• test_fccAl_DGSSXRes.py
• Where to put "ellipse" module used by VERDI?

[yxqd]

@ckendrick Could you please check if I miss any tests? Thanks