Don't hardcode node version
Don't hardcode node version

See: 
https://github.com/github/hubot/blob/master/package.json#L34
https://github.com/github/generator-hubot/blob/master/package.json#L14
https://github.com/yeoman/yo/blob/master/package.json#L10
StackStorm/hubot-stackstorm,armab/hubot-stackstorm