suggested fix for writing and reading aux arrays
Setting the value of aux_viewer_filename anyway. The case when the file
does not exist is handled in the code later.
Merge pull request #228 from amal-ghamdi/aux_io_fix

suggested fix for writing and reading aux arrays
Add function to return ghost cell centers in Dimension.
Merge pull request #229 from ketch/add_ghost_centers

Add function to return ghost cell centers in Dimension.