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/GearTooth.h

@@ -0,0 +1,31 @@
+/*----------------------------------------------------------------------------*/
+/* 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 <memory>
+#include "Counter.h"
+
+/**
+ * Alias for counter class.
+ * Implement the gear tooth sensor supplied by FIRST. Currently there is no
+ * reverse sensing on the gear tooth sensor, but in future versions we might
+ * implement the necessary timing in the FPGA to sense direction.
+ */
+class GearTooth : public Counter {
+ public:
+  /// 55 uSec for threshold
+  static constexpr double kGearToothThreshold = 55e-6;
+  GearTooth(uint32_t channel, bool directionSensitive = false);
+  GearTooth(DigitalSource* source, bool directionSensitive = false);
+  GearTooth(std::shared_ptr<DigitalSource> source,
+            bool directionSensitive = false);
+  virtual ~GearTooth() = default;
+  void EnableDirectionSensing(bool directionSensitive);
+
+  virtual std::string GetSmartDashboardType() const override;
+};