Fix null pointer reference for "smix reverse"

Fix null pointer reference for "smix reverse"
The short syntax `smix reverse` is meant to print the table. When the logic was checking for parameters it was failing to deal with the null pointer when no parameters were present. Additionally the `smix reverse` was called at the end of a successful command to display the table so even though the command was succeeding it was crashing on the null pointer reference when trying to display the result.

Also some stylistic cleanup