Refactoring: Benchmarking the First Improvement

        $ perl ~/gitwork/myscripts/compare_git_versions/compare_git_versions \
        >         --workdir=/home/jkeenan/gitwork/list-compare \
        >         --program=/home/jkeenan/learn/perl/lc/get_3_intersection.pl \
        >         --before=v0.38 \
        >         --after=speedup_get_intersection \
        >         --benchmarks-only

      HEAD is now at daa3559... Update support information.  v0.38.
      ok 1 - Running benchmarks only
      List::Compare::Functional version: 0.38000
      timethis 1000:  2 wallclock secs ( 1.34 usr +  0.00 sys =  1.34 CPU) @ 746.27/s (n=1000)
      1..1

      HEAD is now at e565fb3... CPAN version 0.51.
      ok 1 - Running benchmarks only
      List::Compare::Functional version: 0.51000
      timethis 1000:  1 wallclock secs ( 1.32 usr +  0.00 sys =  1.32 CPU) @ 757.58/s (n=1000)
      1..1