Add option `-nodisplay` for Matlab

This is useful when we run the script through batch scheduling.

Convert_Matlab/inst_eddies_v6.py

@@ -143,7 +143,7 @@ while True:
     if os.access(adt_file, os.R_OK):
         print("Processing", my_date, "...")
         os.symlink(adt_file, "adt.mat")
-        pty.spawn(["matlab", "-nojvm", "-r", "inst_eddies"])
+        pty.spawn(["matlab", "-nojvm", "-nodisplay", "-r", "inst_eddies"])
         matlab_data = sio.loadmat("adt_v6.mat", squeeze_me = True,
                                   variable_names = ("date_num", "X", "Y",
                                                     "Anticyclonic_Cell",