CDClient cleanup and optimization (#1023)

* CDClient cleanup and optimization

- Use static function to get table name
- Remove unused GetName function
- Replace above function with a static GetTableName function
- Remove verbose comments
- Remove verbose initializers
- Remove need to specify table name when getting a table by name
- Remove unused typedef for mac and linux

* Re-add unused table

Convert tables to singletons

- Convert all CDClient tables to singletons
- Move Singleton.h to dCommon
- Reduce header clutter in CDClientManager

dCommon/Singleton.h

@@ -0,0 +1,19 @@
+#pragma once
+
+template <typename T>
+class Singleton {
+public:
+	static T& Instance() {
+		static T instance{};
+		return instance;
+	}
+
+	virtual ~Singleton() = default;
+	Singleton(const Singleton& other) = delete;
+	Singleton(Singleton&& other) = delete;
+	Singleton& operator=(const Singleton& other) = delete;
+	Singleton& operator=(Singleton&& other) = delete;
+
+protected:
+	Singleton() = default;
+};

dCommon/dEnums/dCommonVars.h

@@ -64,11 +64,6 @@ typedef std::set<LWOOBJID> TSetObjID;
 
 const float PI = 3.14159f;
 
-#if defined(__unix) || defined(__APPLE__)
-//For Linux:
-typedef __int64_t __int64;
-#endif
-
 //============ STRUCTS ==============
 
 struct LWOSCENEID {