ConfigUtility now supports recursion; is a Singleton

If you have "config.next" set, the config system will load that as another
config file. Higher config files have a higher precedence over subfiles
when conflicting keys are encountered.

* Added singleton.hpp, containing Singleton<T>
* ConfigUtility now inherits from Singleton
* Tweaked timer.*pp layouts

common/utilities/singleton.hpp

@@ -0,0 +1,63 @@
+/* Copyright: (c) Kayne Ruse 2014
+ * 
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ * 
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ * 
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ * 
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 
+ * 3. This notice may not be removed or altered from any source
+ * distribution.
+*/
+#ifndef SINGLETON_HPP_
+#define SINGLETON_HPP_
+
+#include <stdexcept>
+
+template<typename T>
+class Singleton {
+public:
+	static T& GetSingleton() {
+		if (!ptr) {
+			throw(std::logic_error("This singleton has not been created"));
+		}
+		return *ptr;
+	}
+	static void Create() {
+		if (ptr) {
+			throw(std::logic_error("This singleton has already been created"));
+		}
+		ptr = new T();
+	}
+	static void Delete() {
+		if (!ptr) {
+			throw(std::logic_error("A non-existant singleton cannot be deleted"));
+		}
+		delete ptr;
+		ptr = nullptr;
+	}
+
+protected:
+	Singleton() = default;
+	Singleton(Singleton const&) = default;
+	Singleton(Singleton&&) = default;
+	~Singleton() = default;
+
+private:
+	static T* ptr;
+};
+
+template<typename T>
+T* Singleton<T>::ptr = nullptr;
+
+#endif