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/athena/include/PWMSpeedController.h

@@ -0,0 +1,34 @@
+/*----------------------------------------------------------------------------*/
+/* 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 "SafePWM.h"
+#include "SpeedController.h"
+
+/**
+ * Common base class for all PWM Speed Controllers
+ */
+class PWMSpeedController : public SafePWM, public SpeedController {
+ public:
+  virtual ~PWMSpeedController() = default;
+  virtual void Set(float value, uint8_t syncGroup = 0) override;
+  virtual float Get() const override;
+  virtual void Disable() override;
+  virtual void StopMotor() override;
+
+  virtual void PIDWrite(float output) override;
+
+  virtual void SetInverted(bool isInverted) override;
+  virtual bool GetInverted() const override;
+
+ protected:
+  explicit PWMSpeedController(uint32_t channel);
+
+ private:
+  bool m_isInverted = false;
+};