Use a (mostly) hermetic Python interpreter

It still requires python to be installed on the host to run the wrapper
scripts, but it's close to being fully hermetic.

This also requires/enables the following changes, unfortunately all at
the same time:
 * Use a downloaded f2py
 * Use a downloaded scipy/numpy/matplotlib
 * Fix a few things that don't run with the python version in their #!
 * Stop using bazel-generated __init__.py files, because those interfere
   with importing matplotlib nicely

Change-Id: Ife280464613d67cece9587b7d947f0b1d5466d7e
diff --git a/y2012/BUILD b/y2012/BUILD
index 27ea143..097ea57 100644
--- a/y2012/BUILD
+++ b/y2012/BUILD
@@ -1,70 +1,76 @@
-load('//aos/downloader:downloader.bzl', 'aos_downloader')
+load("//aos/downloader:downloader.bzl", "aos_downloader")
 
 cc_binary(
-  name = 'joystick_reader',
-  srcs = [
-    'joystick_reader.cc',
-  ],
-  deps = [
-    '//aos/input:joystick_input',
-    '//aos/linux_code:init',
-    '//aos/common/logging',
-    '//aos/common:time',
-    '//aos/common/util:log_interval',
-    '//aos/common/actions:action_lib',
-    '//frc971/control_loops/drivetrain:drivetrain_queue',
-    '//y2012/control_loops/accessories:accessories_queue',
-    '//frc971/queues:gyro',
-    '//frc971/autonomous:auto_queue',
-  ],
+    name = "joystick_reader",
+    srcs = [
+        "joystick_reader.cc",
+    ],
+    deps = [
+        "//aos/common:time",
+        "//aos/common/actions:action_lib",
+        "//aos/common/logging",
+        "//aos/common/util:log_interval",
+        "//aos/input:joystick_input",
+        "//aos/linux_code:init",
+        "//frc971/autonomous:auto_queue",
+        "//frc971/control_loops/drivetrain:drivetrain_queue",
+        "//frc971/queues:gyro",
+        "//y2012/control_loops/accessories:accessories_queue",
+    ],
 )
 
 aos_downloader(
-  name = 'download',
-  start_srcs = [
-    ':joystick_reader',
-    ':wpilib_interface',
-    '//y2012/control_loops/drivetrain',
-    '//y2012/control_loops/accessories',
-    '//aos:prime_start_binaries',
-  ],
-  srcs = [
-    '//aos:prime_binaries',
-  ],
-  restricted_to = ['//tools:roborio'],
+    name = "download",
+    srcs = [
+        "//aos:prime_binaries",
+    ],
+    restricted_to = ["//tools:roborio"],
+    start_srcs = [
+        ":joystick_reader",
+        ":wpilib_interface",
+        "//y2012/control_loops/drivetrain",
+        "//y2012/control_loops/accessories",
+        "//aos:prime_start_binaries",
+    ],
 )
 
 cc_binary(
-  name = 'wpilib_interface',
-  srcs = [
-    'wpilib_interface.cc',
-  ],
-  deps = [
-    '//aos/common/controls:control_loop',
-    '//aos/common/logging',
-    '//aos/common/logging:queue_logging',
-    '//aos/common/messages:robot_state',
-    '//aos/common/util:log_interval',
-    '//aos/common/util:phased_loop',
-    '//aos/common/util:wrapping_counter',
-    '//aos/common:stl_mutex',
-    '//aos/common:time',
-    '//aos/linux_code:init',
-    '//frc971/control_loops/drivetrain:drivetrain_queue',
-    '//frc971/control_loops:queues',
-    '//frc971/wpilib:buffered_pcm',
-    '//frc971/wpilib:dma',
-    '//frc971/wpilib:dma_edge_counting',
-    '//frc971/wpilib:encoder_and_potentiometer',
-    '//frc971/wpilib:gyro_sender',
-    '//frc971/wpilib:interrupt_edge_counting',
-    '//frc971/wpilib:joystick_sender',
-    '//frc971/wpilib:logging_queue',
-    '//frc971/wpilib:loop_output_handler',
-    '//frc971/wpilib:wpilib_interface',
-    '//frc971/wpilib:wpilib_robot_base',
-    '//third_party:wpilib',
-    '//y2012/control_loops/accessories:accessories_queue',
-  ],
-  restricted_to = ['//tools:roborio'],
+    name = "wpilib_interface",
+    srcs = [
+        "wpilib_interface.cc",
+    ],
+    restricted_to = ["//tools:roborio"],
+    deps = [
+        "//aos/common:stl_mutex",
+        "//aos/common:time",
+        "//aos/common/controls:control_loop",
+        "//aos/common/logging",
+        "//aos/common/logging:queue_logging",
+        "//aos/common/messages:robot_state",
+        "//aos/common/util:log_interval",
+        "//aos/common/util:phased_loop",
+        "//aos/common/util:wrapping_counter",
+        "//aos/linux_code:init",
+        "//frc971/control_loops:queues",
+        "//frc971/control_loops/drivetrain:drivetrain_queue",
+        "//frc971/wpilib:buffered_pcm",
+        "//frc971/wpilib:dma",
+        "//frc971/wpilib:dma_edge_counting",
+        "//frc971/wpilib:encoder_and_potentiometer",
+        "//frc971/wpilib:gyro_sender",
+        "//frc971/wpilib:interrupt_edge_counting",
+        "//frc971/wpilib:joystick_sender",
+        "//frc971/wpilib:logging_queue",
+        "//frc971/wpilib:loop_output_handler",
+        "//frc971/wpilib:wpilib_interface",
+        "//frc971/wpilib:wpilib_robot_base",
+        "//third_party:wpilib",
+        "//y2012/control_loops/accessories:accessories_queue",
+    ],
+)
+
+py_library(
+    name = "python_init",
+    srcs = ["__init__.py"],
+    visibility = ["//visibility:public"],
 )
diff --git a/y2012/__init__.py b/y2012/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/y2012/__init__.py
diff --git a/y2012/control_loops/BUILD b/y2012/control_loops/BUILD
new file mode 100644
index 0000000..613ddd4
--- /dev/null
+++ b/y2012/control_loops/BUILD
@@ -0,0 +1,6 @@
+py_library(
+    name = "python_init",
+    srcs = ["__init__.py"],
+    visibility = ["//visibility:public"],
+    deps = ["//y2012:python_init"],
+)
diff --git a/y2012/control_loops/__init__.py b/y2012/control_loops/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/y2012/control_loops/__init__.py
diff --git a/y2012/control_loops/python/BUILD b/y2012/control_loops/python/BUILD
index b29f7bd..f10d6fa 100644
--- a/y2012/control_loops/python/BUILD
+++ b/y2012/control_loops/python/BUILD
@@ -1,42 +1,53 @@
-package(default_visibility = ['//y2012:__subpackages__'])
+package(default_visibility = ["//y2012:__subpackages__"])
 
 py_binary(
-  name = 'drivetrain',
-  srcs = [
-    'drivetrain.py',
-  ],
-  deps = [
-    '//external:python-gflags',
-    '//external:python-glog',
-    '//frc971/control_loops/python:drivetrain',
-  ],
-  restricted_to = ['//tools:k8'],
+    name = "drivetrain",
+    srcs = [
+        "drivetrain.py",
+    ],
+    legacy_create_init = False,
+    restricted_to = ["//tools:k8"],
+    deps = [
+        ":python_init",
+        "//external:python-gflags",
+        "//external:python-glog",
+        "//frc971/control_loops/python:drivetrain",
+    ],
 )
 
 py_binary(
-  name = 'polydrivetrain',
-  srcs = [
-    'polydrivetrain.py',
-    'drivetrain.py',
-  ],
-  deps = [
-    '//external:python-gflags',
-    '//external:python-glog',
-    '//frc971/control_loops/python:polydrivetrain',
-  ],
-  restricted_to = ['//tools:k8'],
+    name = "polydrivetrain",
+    srcs = [
+        "drivetrain.py",
+        "polydrivetrain.py",
+    ],
+    legacy_create_init = False,
+    restricted_to = ["//tools:k8"],
+    deps = [
+        ":python_init",
+        "//external:python-gflags",
+        "//external:python-glog",
+        "//frc971/control_loops/python:polydrivetrain",
+    ],
 )
 
 py_library(
-  name = 'polydrivetrain_lib',
-  srcs = [
-    'polydrivetrain.py',
-    'drivetrain.py',
-  ],
-  deps = [
-    '//external:python-gflags',
-    '//external:python-glog',
-    '//frc971/control_loops/python:controls',
-  ],
-  restricted_to = ['//tools:k8'],
+    name = "polydrivetrain_lib",
+    srcs = [
+        "drivetrain.py",
+        "polydrivetrain.py",
+    ],
+    restricted_to = ["//tools:k8"],
+    deps = [
+        "//external:python-gflags",
+        "//external:python-glog",
+        "//frc971/control_loops/python:controls",
+    ],
+)
+
+py_library(
+    name = "python_init",
+    srcs = ["__init__.py"],
+    visibility = ["//visibility:public"],
+    deps = ["//y2012/control_loops:python_init"],
 )
diff --git a/y2012/control_loops/python/__init__.py b/y2012/control_loops/python/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/y2012/control_loops/python/__init__.py