Add remote timestamps and queue_index to context

This gives us the knobs to expose the remote timestamps and queue_index
to anything receiving the events.  The first use case is the logger.  It
can now log forwarded entries *without* having to make the
message_gateway responsible for logging this data.

Change-Id: Ie34dd040d270f4fa90ecd6e463069e1adca1818a
diff --git a/y2017/control_loops/superstructure/superstructure.cc b/y2017/control_loops/superstructure/superstructure.cc
index 29886e2..a0448fd 100644
--- a/y2017/control_loops/superstructure/superstructure.cc
+++ b/y2017/control_loops/superstructure/superstructure.cc
@@ -138,7 +138,7 @@
           status->fbb());
   flatbuffers::Offset<ShooterStatus> shooter_offset = shooter_.Iterate(
       unsafe_goal != nullptr ? &shooter_goal : nullptr,
-      position->theta_shooter(), position_context().monotonic_sent_time,
+      position->theta_shooter(), position_context().monotonic_event_time,
       output != nullptr ? &(output_struct.voltage_shooter) : nullptr,
       status->fbb());