config: enable P2P by default

config.js

     // the room. If that succeeds the conference will stop sending data through
     // the JVB and use the peer to peer connection instead. When 3rd participant
     // joins the conference will be moved back to the JVB connection.
-    //enableP2P: true
+    enableP2P: true
     // How long we're going to wait, before going back to P2P after
     // the 3rd participant has left the conference (to filter out page reload)
     //backToP2PDelay: 5