Convert ControlLoop over to using EventLoop

Next step is to pass in the event loop and flip over to using it in
tests and at runtime.

Change-Id: Ia3b8f099e4eacc0ffa8fbfe00d651f3684a8c783
diff --git a/aos/events/event-loop.h b/aos/events/event-loop.h
index 57ff49b..0b336c3 100644
--- a/aos/events/event-loop.h
+++ b/aos/events/event-loop.h
@@ -107,6 +107,7 @@
   //
   // This will watch messages sent to path.
   // Note that T needs to match both send and recv side.
+  // TODO(parker): Need to support ::std::bind.  For now, use lambdas.
   template <typename Watch>
   void MakeWatcher(const std::string &path, Watch &&w);