This port contains utilities to analyse and publish Go benchmark
results.  The main use case is to compare two series of benchmarks
for minuscule performance improvements.  Four programs are included:
 - benchstat is a command-line tool that computes and compares
   statistics about benchmarks
 - benchsave is a command-line tool for publishing benchmark results
 - localperfdata is a local version of the https://perfdata.golang.org/
   benchmark result storage system
 - localperf is a local version of the https://perf.golang.org/
   benchmark result analysis system.