Rename recordrtc npm package to recordrtc-nodejs and ship base js as RecordRTC

Renames the RecordRTC nodejs demo to 'recordrtc-nodejs' in its package.json.

And adds a package.json to the RecordRTC top level so that Record RTC can be made included as a package just for the JS. I should possibly specify which files to include so we **only** get RecordRTC.js not all the examples.