Add atmosphere.js 2.0.0.RC2

Hello,

I'd like to add the JavaScript clients for Atmosphere.

* https://github.com/Atmosphere/atmosphere
* https://github.com/Atmosphere/atmosphere-javascript

For your information, atmosphre.js and jquery.atmosphere.js were originally located in Atmosphere/atmosphere (1200+ stargazers) and recently moved to new repository Atmosphere/atmosphere-javascript

Files: 
For atmosphere.js - https://github.com/Atmosphere/atmosphere-javascript/tree/javascript-project-2.0.0.RC2/modules/javascript/src/main/webapp/javascript
For jquery.atmosphere.js - https://github.com/Atmosphere/atmosphere-javascript/tree/javascript-project-2.0.0.RC2/modules/jquery/src/main/webapp/jquery