Quiet mode: suppress output that is not an error.

[pete4abw]

If scrub is called from within a file manager or other application, output to stdout and possibly stderr, is not required. Suggest adding a new option " -q " to enable quiet mode (think of the way shred operates by default). The quiet option could be an if !quiet then print wrapper around any printf statement or a #define could be added to make the print function intelligent.
On a related matter, the mix of printf, fprintf, is messy. Should adopt a standard output methodology. Here again a #define printf would be useful.

#define print_on_error function...
#define print_standard function...
#define print_progress function...