Add confidence to TargetPose flatbuffer

Will be used for further filtering in the localizer.

Signed-off-by: milind-u <milind.upadhyay@gmail.com>
Change-Id: Idf9781cfda424a0e43a341c0da93c4d895439da1
diff --git a/frc971/vision/target_map.fbs b/frc971/vision/target_map.fbs
index ed87895..b3fd6e9 100644
--- a/frc971/vision/target_map.fbs
+++ b/frc971/vision/target_map.fbs
@@ -24,6 +24,13 @@
   // Quaterniond(orientation.w(), orientation.x(), orientation.y(), orientation.z())
   position:Position (id: 1);
   orientation:Quaternion (id: 2);
+
+  // Minimum decision margin (confidence) for this april tag detection.
+  // Only filled out if this pose represents a live detection.
+  // NOTE: Detections with a decision margin less than
+  // FLAGS_min_decision_margin in aprilrobotics.cc are already filtered
+  // out before sending.
+  confidence:double (id: 3);
 }
 
 // Map of all target poses on a field.