Move y2012 over to new SensorReader class

While we are here, shove the RobotState sender and DMA tick code into
the base class.

Change-Id: I49e6b3902c1ee46d396ccc77c2b8dce825e891d8
diff --git a/y2012/BUILD b/y2012/BUILD
index 5e85c3d..159632b 100644
--- a/y2012/BUILD
+++ b/y2012/BUILD
@@ -57,6 +57,7 @@
         "//frc971/wpilib:joystick_sender",
         "//frc971/wpilib:logging_queue",
         "//frc971/wpilib:loop_output_handler",
+        "//frc971/wpilib:sensor_reader",
         "//frc971/wpilib:wpilib_interface",
         "//frc971/wpilib:wpilib_robot_base",
         "//third_party:wpilib",