[11283] Drop the no longer used Visual Leak Detector (VLD)

For leak detection you can also use tools like Valgrind.

If you really want to use VLD you can revert this commit and remove the comments in MemoryLeaks.cpp and MemoryLeaks.h.
The VLD version which has been shipped with MaNGOS is *heavily* outdated and I thus suggest you to use a newer version of it, if you really plan to use it. You can find the newest version on github in its official repository: https://github.com/dmoulding/vld

src/mangosd/Main.cpp

@@ -72,11 +72,6 @@ void usage(const char *prog)
 /// Launch the mangos server
 extern int main(int argc, char **argv)
 {
-    // - Construct Memory Manager Instance
-    MaNGOS::Singleton<MemoryManager>::Instance();
-
-    //char *leak = new char[1000];                          // test leak detection
-
     ///- Command line parsing
     char const* cfg_file = _MANGOSD_CONFIG;