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/SafePWM.h

@@ -0,0 +1,45 @@
+/*----------------------------------------------------------------------------*/
+/* 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 <memory>
+
+#include "MotorSafety.h"
+#include "MotorSafetyHelper.h"
+#include "PWM.h"
+#include "llvm/raw_ostream.h"
+
+namespace frc {
+
+/**
+ * A safe version of the PWM class.
+ * It is safe because it implements the MotorSafety interface that provides
+ * timeouts in the event that the motor value is not updated before the
+ * expiration time. This delegates the actual work to a MotorSafetyHelper
+ * object that is used for all objects that implement MotorSafety.
+ */
+class SafePWM : public PWM, public MotorSafety {
+ public:
+  explicit SafePWM(int channel);
+  virtual ~SafePWM() = default;
+
+  void SetExpiration(double timeout);
+  double GetExpiration() const;
+  bool IsAlive() const;
+  void StopMotor();
+  bool IsSafetyEnabled() const;
+  void SetSafetyEnabled(bool enabled);
+  void GetDescription(llvm::raw_ostream& desc) const;
+
+  virtual void SetSpeed(double speed);
+
+ private:
+  std::unique_ptr<MotorSafetyHelper> m_safetyHelper;
+};
+
+}  // namespace frc