Increase number of timing report senders.

With all the threads in wpilib, we blew through the number of senders.

We have no logged data, so this is a fine schema breaking change.

Change-Id: I62381faf9e0f96750e68aacca4a139e8af7ac961
diff --git a/aos/configuration.fbs b/aos/configuration.fbs
index a5cb59f..a9e71ea 100644
--- a/aos/configuration.fbs
+++ b/aos/configuration.fbs
@@ -15,6 +15,11 @@
   // computed in the future.)
   max_size:int = 1000;
 
+  // Sets the maximum number of senders on a channel.
+  num_senders:int = 10;
+  // Sets the maximum number of watchers on a channel.
+  num_watchers:int = 10;
+
   // The schema for the data sent on this channel.
   schema:reflection.Schema;
 }