Support new WebSocket signaling format.

- Support new GAE message format and new signaling
sequence, which allows connection to 3-dot-apprtc server.
- Add UI setting to switch between GAE / WebSockets signaling.
- Some clean ups to better support command line application
execution.

BUG=3937,3995,4041
R=jiayl@webrtc.org, tkchin@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/27319004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7813 4adac7df-926f-26a2-2b94-8c16560cd09d

talk/examples/android/src/org/appspot/apprtc/PeerConnectionClient.java

@@ -283,6 +283,7 @@ public class PeerConnectionClient {
   }
 
   private void reportError(final String errorMessage) {
+    Log.e(TAG, "Peerconnection error: " + errorMessage);
     activity.runOnUiThread(new Runnable() {
       public void run() {
         events.onPeerConnectionError(errorMessage);