copy benchmark.js to gzip-benchmark.js
add gzip-benchmark-minify utility script
change gzip-benchmark.js to use gzipped files for stats
add commands for running benchamrks to README.md
Include gzip in benchmarks

Gzip original corpus
Gzip minified corpus
Compare original gzip size to minified gzip size
Eliminate averages (size/time) from output
Tuck away generated benchmark artifacts
Merge pull request #239 from duncanbeevers/gzip-benchmark

Gzip benchmark