"Decommissioning" update_cube for now (#100)

* "Decommissioning" `update_cube` for now

`update_cube` -> `_update_cube`

* Updating reference to update_cube in test_make_cube.py

Author: jaymedina

astrocut/make_cube.py

@@ -719,7 +719,7 @@ def _write_info_table(self):
             cube_hdus.append(table_hdu)
 
 
-    def update_cube(self, file_list, cube_file, sector=None, max_memory=50, verbose=True):
+    def _update_cube(self, file_list, cube_file, sector=None, max_memory=50, verbose=True):
         """ Updates an existing cube file if one has already been made and a new delivery is being appended to it. 
         Same functionality as make_cube(...), but working on an already existing file rather than building a new one. 
         This function will: 

astrocut/tests/test_make_cube.py

@@ -92,7 +92,7 @@ def test_make_and_update_cube(tmpdir):
 
     # Testing update_cube
 
-    cube_file = cube_maker.update_cube(ffi_files[num_im // 2:], cube_file, verbose=False)
+    cube_file = cube_maker._update_cube(ffi_files[num_im // 2:], cube_file, verbose=False)
 
     hdu = fits.open(cube_file)
     cube = hdu[1].data