Add Turret BUILD and turret.py

Create turret.py based on the 2019 season's wrist, and turret/BUILD in the superstructure.

Change-Id: If4369697fc1dc8a01740a50b90d9ae5d2491a476
diff --git a/y2020/control_loops/superstructure/turret/BUILD b/y2020/control_loops/superstructure/turret/BUILD
new file mode 100644
index 0000000..894d418
--- /dev/null
+++ b/y2020/control_loops/superstructure/turret/BUILD
@@ -0,0 +1,32 @@
+package(default_visibility = ["//y2020:__subpackages__"])
+
+genrule(
+    name = "genrule_turret",
+    outs = [
+        "turret_plant.h",
+        "turret_plant.cc",
+        "integral_turret_plant.h",
+        "integral_turret_plant.cc",
+    ],
+    cmd = "$(location //y2020/control_loops/python:turret) $(OUTS)",
+    tools = [
+        "//y2020/control_loops/python:turret",
+    ],
+)
+
+cc_library(
+    name = "turret_plants",
+    srcs = [
+        "integral_turret_plant.cc",
+        "turret_plant.cc",
+    ],
+    hdrs = [
+        "integral_turret_plant.h",
+        "turret_plant.h",
+    ],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//frc971/control_loops:hybrid_state_feedback_loop",
+        "//frc971/control_loops:state_feedback_loop",
+    ],
+)