added chris-lea repo and changed all npm references to nodejs

This change is required to pass the "Install edx-platform npm dependencies" when deploying against the 10-16-2014 edx-platform release; can't install uglifyjs (referenced in package.json) otherwise due to error "UNKNOWN". ;)
This is fixed in the latest nodejs package available in ppa:chris-lea/node.js

```
stderr: npm http GET http://registry.npmjs.org/coffee-script/1.6.1
npm http GET http://registry.npmjs.org/uglify-js/2.4.15
npm http 304 http://registry.npmjs.org/uglify-js/2.4.15
npm http 304 http://registry.npmjs.org/coffee-script/1.6.1
npm http GET http://registry.npmjs.org/source-map/0.1.34
npm http GET http://registry.npmjs.org/async
npm http GET http://registry.npmjs.org/uglify-to-browserify
npm http GET http://registry.npmjs.org/optimist
npm http 304 http://registry.npmjs.org/async
npm http 304 http://registry.npmjs.org/optimist
npm http 304 http://registry.npmjs.org/uglify-to-browserify
npm http 304 http://registry.npmjs.org/source-map/0.1.34
npm ERR! error installing uglify-js@2.4.15
npm ERR! error rolling back uglify-js@2.4.15 Error: UNKNOWN, unknown error '/edx/app/edxapp/edx-platform/node_modules/uglify-js'


npm ERR! 
npm ERR! System Linux 3.8.0-39-generic
npm ERR! command "node" "/usr/bin/npm" "install"
npm ERR! cwd /edx/app/edxapp/edx-platform
npm ERR! node -v v0.6.12
npm ERR! npm -v 1.1.4
npm ERR! code ENOTSUP
npm ERR! message Unsupported
npm ERR! errno {}
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /edx/app/edxapp/edx-platform/npm-debug.log
npm not ok
```