Change transfer of acqs_init cols into self

Somewhere between numpy 1.12 and 1.15 the
behavior of argsort changed so that
np.argsort([0] * 20) might not be stable.
Table was relying on that (upstream fix needed),
but in the meantime adding columns like this is
now efficient in astropy Table.

proseco/acq.py

@@ -628,7 +628,8 @@ def get_initial_catalog(self):
         acqs_init = cand_acqs[acq_indices]
 
         # Transfer to acqs (which at this point is an empty table)
-        self.add_columns(acqs_init.columns.values())
+        for col in acqs_init.itercols():
+            self[col.info.name] = col
 
     def calc_p_brightest(self, acq, box_size, man_err=0, bgd=0):
         """