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/intake/BUILD b/y2017/control_loops/superstructure/intake/BUILD
index 550c241..00642b0 100644
--- a/y2017/control_loops/superstructure/intake/BUILD
+++ b/y2017/control_loops/superstructure/intake/BUILD
@@ -43,6 +43,7 @@
     deps = [
         ":intake_plants",
         "//frc971/control_loops:profiled_subsystem",
+        "//frc971/zeroing:pot_and_absolute_encoder",
         "//y2017:constants",
         "//y2017/control_loops/superstructure:superstructure_goal_fbs",
     ],