Update intercom.io.js

Changed to the newest version of the API: http://doc.intercom.io/api/, rather than the /v1/ version.
Added a getSegment function, which should be able to perform the listSegments and the getSegment(segment_id) functions.
Updated readme.md for new API

Added new methods and removed legacy /v1/ methods
Switched over to new API (not /v1/)

Due to impending deprecation of /v1/ API [Officially deprecated on June 17th](http://doc.intercom.io/api/v1/). No longer supports the original calls made by the legacy API.
Update package.json
Update Readme.md
Merge pull request #2 from mcdonamp/master

Hard fork to the new API