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/MotorSafetyHelper.h

@@ -0,0 +1,49 @@
+/*----------------------------------------------------------------------------*/
+/* 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 <set>
+
+#include "ErrorBase.h"
+#include "HAL/cpp/priority_mutex.h"
+
+namespace frc {
+
+class MotorSafety;
+
+class MotorSafetyHelper : public ErrorBase {
+ public:
+  explicit MotorSafetyHelper(MotorSafety* safeObject);
+  ~MotorSafetyHelper();
+  void Feed();
+  void SetExpiration(double expirationTime);
+  double GetExpiration() const;
+  bool IsAlive() const;
+  void Check();
+  void SetSafetyEnabled(bool enabled);
+  bool IsSafetyEnabled() const;
+  static void CheckMotors();
+
+ private:
+  // the expiration time for this object
+  double m_expiration;
+  // true if motor safety is enabled for this motor
+  bool m_enabled;
+  // the FPGA clock value when this motor has expired
+  double m_stopTime;
+  // protect accesses to the state for this object
+  mutable hal::priority_recursive_mutex m_syncMutex;
+  // the object that is using the helper
+  MotorSafety* m_safeObject;
+  // List of all existing MotorSafetyHelper objects.
+  static std::set<MotorSafetyHelper*> m_helperList;
+  // protect accesses to the list of helpers
+  static hal::priority_recursive_mutex m_listMutex;
+};
+
+}  // namespace frc