Update CHANGELOG.md

@unsymbol I see (from twitter) you've noticed my experimentation with you ribiprocessing, I hope you like it.  To compile I find I need to use `jruby -S rake` rather than rake even when I've only got jruby installed (as I have under linux-Mint). I am 100% linux guy and mainly use ArchLinux.
I came to your project via a problem I was having with jruby-9000 (HEAD) in running many ruby-processing sketches. When I confirmed that there was the same issue with ribiprocessing I offered [that to the jruby developers as a much simpler test tool.](https://github.com/jruby/jruby/issues/1917#issuecomment-56238417 ). Recently I've been doing a fair bit of re-factoring of ruby-processing and I could see things I might like to try out with ribiprocessing, so hence this effort.