@BurntSushi rightly reported that the 0.3.0 benchmarks do not pass '-u' to rg, thus giving the other utilities which don't look at .gitignore files an arguable unfair advantage. Address this.

Also, document how to obtain the corpi and run the benchmarks. This was slated for 0.3.0 (in my best intentions at least), but didn't make it. Maybe add rg's Linux corpus into the mix as well, it's a more

Running broken-link-checker on beyondgrep.com gives us these errors:

$ blc -r https://beyondgrep.com/ | ack 'Getting|BROKEN'
Getting links from: https://beyondgrep.com/
Getting links from: https://beyondgrep.com/why-ack/
├─BROKEN─ http://www.unixlore.net/use-ack-as-better-grep.html (HTTP_403)
├─BROKEN─ http://www.just-another.net/