Split up zeroing library BUILD rules

There was no good reason for one build rule to have both the interface
and a bunch of implementations; split it up and make the relevant users
depend on the libraries directly.

Change-Id: If6a0aa49dd7ea588b7325604658bc0594db4aac0
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/y2020/control_loops/superstructure/superstructure.h b/y2020/control_loops/superstructure/superstructure.h
index 5d371fc..8a00bf0 100644
--- a/y2020/control_loops/superstructure/superstructure.h
+++ b/y2020/control_loops/superstructure/superstructure.h
@@ -5,6 +5,9 @@
 #include "frc971/control_loops/control_loop.h"
 #include "frc971/control_loops/drivetrain/drivetrain_status_generated.h"
 #include "frc971/input/joystick_state_generated.h"
+#include "frc971/zeroing/absolute_and_absolute_encoder.h"
+#include "frc971/zeroing/absolute_encoder.h"
+#include "frc971/zeroing/pot_and_absolute_encoder.h"
 #include "y2020/constants.h"
 #include "y2020/control_loops/superstructure/hood/hood_encoder_zeroing_estimator.h"
 #include "y2020/control_loops/superstructure/shooter/shooter.h"