Get adventurous with the build matrix.
Get adventurous with the build matrix.

On a serious note, here's why I chose the runtimes I did:

- RubyRacer: we use this at NUBIC
- Node: it's still V8, but a separate process, so should reveal any bad
  assumptions about (lack of) persisted state between calls
- Johnson: uses Mozilla SpiderMonkey, an independent Javascript
  implementation

NUBIC/jsv.rb