Update to 2018_v4 image and new build system. (#598)

* Revert "Force OpenCV to 3.1.0 (#602)"

This reverts commit 50ed55e8e2.

* Removes Simulation

* Removes old build system

* Removes old gtest

* Adds new gmock and gtest

* Updates to new ni-libraries

* removes MyRobot (to be replaced)

* moves files to new location

* Adds new sim backend and new test executables

* updates .styleguide and .gitignore

* Changes cpp WPILibVersion to a function

MSVC throws an AV with the old version.

* Disables USBCamera on all systems except for linux

* 2018 NI Libraries

* New build system

wpilibc/src/main/native/include/Ultrasonic.h

@@ -0,0 +1,102 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2008-2017. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <atomic>
+#include <memory>
+#include <set>
+#include <string>
+#include <thread>
+
+#include "Counter.h"
+#include "LiveWindow/LiveWindowSendable.h"
+#include "PIDSource.h"
+#include "SensorBase.h"
+
+namespace frc {
+
+class DigitalInput;
+class DigitalOutput;
+
+/**
+ * Ultrasonic rangefinder class.
+ * The Ultrasonic rangefinder measures absolute distance based on the round-trip
+ * time of a ping generated by the controller. These sensors use two
+ * transducers, a speaker and a microphone both tuned to the ultrasonic range. A
+ * common ultrasonic sensor, the Daventech SRF04 requires a short pulse to be
+ * generated on a digital channel. This causes the chirp to be emitted. A second
+ * line becomes high as the ping is transmitted and goes low when the echo is
+ * received. The time that the line is high determines the round trip distance
+ * (time of flight).
+ */
+class Ultrasonic : public SensorBase,
+                   public PIDSource,
+                   public LiveWindowSendable {
+ public:
+  enum DistanceUnit { kInches = 0, kMilliMeters = 1 };
+
+  Ultrasonic(DigitalOutput* pingChannel, DigitalInput* echoChannel,
+             DistanceUnit units = kInches);
+
+  Ultrasonic(DigitalOutput& pingChannel, DigitalInput& echoChannel,
+             DistanceUnit units = kInches);
+
+  Ultrasonic(std::shared_ptr<DigitalOutput> pingChannel,
+             std::shared_ptr<DigitalInput> echoChannel,
+             DistanceUnit units = kInches);
+  Ultrasonic(int pingChannel, int echoChannel, DistanceUnit units = kInches);
+  virtual ~Ultrasonic();
+
+  void Ping();
+  bool IsRangeValid() const;
+  static void SetAutomaticMode(bool enabling);
+  double GetRangeInches() const;
+  double GetRangeMM() const;
+  bool IsEnabled() const { return m_enabled; }
+  void SetEnabled(bool enable) { m_enabled = enable; }
+
+  double PIDGet() override;
+  void SetPIDSourceType(PIDSourceType pidSource) override;
+  void SetDistanceUnits(DistanceUnit units);
+  DistanceUnit GetDistanceUnits() const;
+
+  void UpdateTable() override;
+  void StartLiveWindowMode() override;
+  void StopLiveWindowMode() override;
+  std::string GetSmartDashboardType() const override;
+  void InitTable(std::shared_ptr<ITable> subTable) override;
+  std::shared_ptr<ITable> GetTable() const override;
+
+ private:
+  void Initialize();
+
+  static void UltrasonicChecker();
+
+  // Time (sec) for the ping trigger pulse.
+  static constexpr double kPingTime = 10 * 1e-6;
+  // Priority that the ultrasonic round robin task runs.
+  static const int kPriority = 64;
+  // Max time (ms) between readings.
+  static constexpr double kMaxUltrasonicTime = 0.1;
+  static constexpr double kSpeedOfSoundInchesPerSec = 1130.0 * 12.0;
+
+  static std::thread
+      m_thread;  // thread doing the round-robin automatic sensing
+  static std::set<Ultrasonic*> m_sensors;       // ultrasonic sensors
+  static std::atomic<bool> m_automaticEnabled;  // automatic round robin mode
+
+  std::shared_ptr<DigitalOutput> m_pingChannel;
+  std::shared_ptr<DigitalInput> m_echoChannel;
+  bool m_enabled = false;
+  Counter m_counter;
+  DistanceUnit m_units;
+
+  std::shared_ptr<ITable> m_table;
+};
+
+}  // namespace frc