blobtool: Error out if extraneous arguments given on command line
blobtool: Error out if extraneous arguments given on command line

- Only allow filename arguments on the command line if we are encoding
a tarball

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr