Fix pcConfig from compiling to a global

But note that maybe we should be constructing a new PCConfig each time
Config is instantiated, rather than sharing it on the prototype.

proxy/config.coffee

@@ -19,8 +19,7 @@ class Config
   connectionsPerClient: 1
 
   # TODO: Different ICE servers.
-  pcConfig = {
+  pcConfig:
     iceServers: [
       { urls: ['stun:stun.l.google.com:19302'] }
     ]
-  }