Convert aos over to flatbuffers

Everything builds, and all the tests pass.  I suspect that some entries
are missing from the config files, but those will be found pretty
quickly on startup.

There is no logging or live introspection of queue messages.

Change-Id: I496ee01ed68f202c7851bed7e8786cee30df29f5
diff --git a/aos/events/pingpong.fbs b/aos/events/pingpong.fbs
new file mode 100644
index 0000000..67e5015
--- /dev/null
+++ b/aos/events/pingpong.fbs
@@ -0,0 +1,14 @@
+namespace aos.examples;
+
+table Ping {
+  value:int;
+  send_time:long;
+}
+
+table Pong {
+  value:int;
+  initial_send_time:long;
+}
+
+root_type Ping;
+root_type Pong;