tests/bench.py: Add a copyright header

Signed-off-by: Gergely Nagy <algernon@balabit.hu>
tests/bench.py: Better result display

Signed-off-by: Gergely Nagy <algernon@balabit.hu>
tests/bench.py: Added a new test to check unification speed

Signed-off-by: Gergely Nagy <algernon@balabit.hu>
tests/bench.py: Make it executable

Signed-off-by: Gergely Nagy <algernon@balabit.hu>