IUS : plusargs makefile variable wasn't getting passed to irun commandline

- running examples/plusargs with SIM=ius didn't show the plusargs defined in
  examples/plusargs/Makefile
examples : making the source of the print/display statements a little clearer

- one my first run through the quickstart wasn't clear to me where the statements
  were coming from in this test. Making it a little more explicit as this is
  the first test that runs when running "make all" from a fresh clone.