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/y2017/control_loops/superstructure/column/column.cc b/y2017/control_loops/superstructure/column/column.cc
index 9acd190..b8a12f7 100644
--- a/y2017/control_loops/superstructure/column/column.cc
+++ b/y2017/control_loops/superstructure/column/column.cc
@@ -11,6 +11,7 @@
 #include "frc971/constants.h"
 #include "frc971/control_loops/profiled_subsystem.h"
 #include "frc971/control_loops/state_feedback_loop.h"
+#include "frc971/zeroing/pulse_index.h"
 #include "y2017/control_loops/superstructure/column/column_integral_plant.h"
 #include "y2017/control_loops/superstructure/column/stuck_column_integral_plant.h"