including the newrelic.coffee script and including required package xml2...

...js

Adds the newrelic me hubot script. for this to work, we have 3 new environment variables.
HUBOT_NEWRELIC_ACCOUNT_ID
HUBOT_NEWRELIC_APP_ID
HUBOT_NEWRELIC_API_KEY

I'll email @carol with what these settings should be set to.