Stats v1 - working code

If you compile Chromium *just now* ( Version 25.0.1358.0 (172326)), and 
go to the following URL:

https://webrtc-demos.appspot.com/html/constraints-and-stats.html

you can see an example of the stats model (v1; v2 won't be implemented 
until it's in the editors' draft) working in practice.

Only stat exposed so far: Audio volume. There will be more.

        Harald