Update cli_printActionPreamble.sh:
    
        - Add verification of FILES variable. This verification was
          previously on cli_getFilesList, but since it has changed to
          output the information, we don't want to output error messages
          here. Presently error messages are printed to standard output
          not the error standard output so this may fill the FILES
          variable with error messages we don't want it to end up with.
          So, we moved the verification from cli_getFilesList to
          cli_printActionPreamble.sh which should be always called after a
          call to cli_getFilesList in order to get the correct flow FILES
          variable definition/verification.
    
        - Verify function parameters. If no action or format is passed to
          this function there is nothing else to do here. This
          verification should be _after_ checking list of files to
          process, so checking list of files to process take place even if
          no preamble message is printed out.