Add multi-node log file reading

This handles timestamps, sorting, and merging with data.

For simplicity, we read the log files once per node.  Once benchmarks
show if this is a bad idea, we can fix it.

Change-Id: I445ac5bfc7186bda25cc899602ac8d95a4cb946d
diff --git a/aos/events/simulated_event_loop.h b/aos/events/simulated_event_loop.h
index 8cff0d7..21b241a 100644
--- a/aos/events/simulated_event_loop.h
+++ b/aos/events/simulated_event_loop.h
@@ -98,6 +98,10 @@
   // Returns the configuration used for everything.
   const Configuration *configuration() const { return configuration_; }
 
+  // Disables forwarding for this channel.  This should be used very rarely only
+  // for things like the logger.
+  void DisableForwarding(const Channel *channel);
+
  private:
   const Configuration *const configuration_;
   EventScheduler scheduler_;