Create python wrapper for spline.

Change-Id: Ia19bb1500542dd886c78cd201b251e6dff2b1d1b
diff --git a/frc971/control_loops/drivetrain/BUILD b/frc971/control_loops/drivetrain/BUILD
index 2bad4d9..c3ea79e 100644
--- a/frc971/control_loops/drivetrain/BUILD
+++ b/frc971/control_loops/drivetrain/BUILD
@@ -294,6 +294,16 @@
     ],
 )
 
+cc_binary(
+    name = "spline.so",
+    srcs = ["libspline.cc"],
+    deps = [
+        ":spline",
+        "//third_party/eigen",
+    ],
+    linkshared=1,
+)
+
 cc_test(
     name = "distance_spline_test",
     srcs = [