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/BUILD b/y2017/control_loops/superstructure/column/BUILD
index 2d83482..6e1cc7f 100644
--- a/y2017/control_loops/superstructure/column/BUILD
+++ b/y2017/control_loops/superstructure/column/BUILD
@@ -71,6 +71,8 @@
         "//frc971:constants",
         "//frc971/control_loops:profiled_subsystem_fbs",
         "//frc971/zeroing",
+        "//frc971/zeroing:hall_effect_and_position",
+        "//frc971/zeroing:pulse_index",
         "//frc971/zeroing:wrap",
         "//y2017:constants",
         "//y2017/control_loops/superstructure:superstructure_position_fbs",