Renamed folders for consistency, using sim/athena/shared schema (#27)

Rename the following folders:
hal/lib/Athena -> hal/lib/athena
hal/lib/Desktop -> hal/lib/sim
hal/lib/Shared -> hal/lib/shared
wpilibc/Athena -> wpilibc/athena
wpilibc/simulation -> wpilibc/sim

Windows users may need to run gradlew clean after updating.

wpilibc/sim/include/MotorSafetyHelper.h

@@ -0,0 +1,44 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2008-2016. 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 "ErrorBase.h"
+#include "HAL/cpp/priority_mutex.h"
+
+#include <set>
+
+class MotorSafety;
+
+class MotorSafetyHelper : public ErrorBase {
+ public:
+  MotorSafetyHelper(MotorSafety* safeObject);
+  ~MotorSafetyHelper();
+  void Feed();
+  void SetExpiration(float expirationTime);
+  float 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 priority_recursive_mutex m_syncMutex;
+  MotorSafety* m_safeObject;  // the object that is using the helper
+  // List of all existing MotorSafetyHelper objects.
+  static std::set<MotorSafetyHelper*> m_helperList;
+  // protect accesses to the list of helpers
+  static priority_recursive_mutex m_listMutex;
+};