Develop datacheck

See merge request !71

Develop merge_across_dims_narm + split_multiselected_dims

See merge request !69

Change final_dims_fake back after reoder array because if retrieve = F, it will be used in attributes later

Move adjusted split dim order part to after 'Detect dimension' print. Then reorder dimension back to the user-required order after getting array.

Add new parameter 'merge_across_dims_narm' and develop codes for the case 'merge_across_dims_narm = TRUE'.

Modify the unit test for the new lon-border-transform fix

See merge request !68

Develop border transform

See merge request !67