Added documentation

include/structures/Clock.hpp

@@ -1,3 +1,11 @@
+/*****************************************************************//**
+ * @file   Clock.hpp
+ * @brief  A small timing utility
+ * 
+ * @author Lauchmelder
+ * @date   April 2021
+ *********************************************************************/
+
 #pragma once
 
 #include "Util.hpp"
@@ -5,12 +13,27 @@
 
 SDLU_BEGIN
 
+/**
+ * @brief Essentially a timer.
+ */
 class Clock
 {
 public:
+	/**
+	 * @brief Creates a new Clock. It has not yet been started, call Restart() before doing anything else.
+	 */
 	Clock();
 
+	/**
+	 * @brief Returns the time elapsed since the last Restart() call.
+	 */
 	Time GetElapsedTime();
+
+	/**
+	 * @brief Restarts the Clock.
+	 * 
+	 * @return The time elapsed since the last Restart() call.
+	 */
 	Time Restart();
 
 private: