feat(Core/Deps): Added fmt lib (#2190)

* About library (https://github.com/fmtlib/fmt)

src/common/Utilities/StringFormat.h

@@ -1,43 +1,33 @@
 /*
+ * Copyright (C) 2016+     AzerothCore <www.azerothcore.org>, released under GNU AGPL v3 license: https://github.com/azerothcore/azerothcore-wotlk/blob/master/LICENSE-AGPL3
  * Copyright (C) 2008-2016 TrinityCore <http://www.trinitycore.org/>
  * Copyright (C) 2005-2009 MaNGOS <http://getmangos.com/>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef __STRING_FORMAT_H__
 #define __STRING_FORMAT_H__
 
-#include <memory>
-#include <iostream>
-#include <string>
-#include <cstdio>
+#include "fmt/printf.h"
 
-namespace Trinity
+namespace ACORE
 {
-    /// Default TC string format function.
-    template<typename... Args>
-    inline std::string StringFormat(const std::string& format, Args const&... args)
+    /// Default AC string format function.
+    template<typename Format, typename... Args>
+    inline std::string StringFormat(Format&& fmt, Args&& ... args)
     {
-        size_t size = std::snprintf(nullptr, 0, format.c_str(), args ...) + 1; // Extra space for '\0'
-        unique_ptr<char[]> buf(new char[size]);
-        std::snprintf(buf.get(), size, format.c_str(), args ...);
-        return std::string(buf.get(), buf.get() + size - 1); // We don
+        try
+        {
+            return fmt::sprintf(std::forward<Format>(fmt), std::forward<Args>(args)...);
+        }
+        catch (const fmt::format_error& formatError)
+        {
+            std::string error = "An error occurred formatting string \"" + std::string(fmt) + "\" : " + std::string(formatError.what());
+            return error;
+        }
     }
 
     /// Returns true if the given char pointer is null.
-    inline bool IsFormatEmptyOrNull(const char* fmt)
+    inline bool IsFormatEmptyOrNull(char const* fmt)
     {
         return fmt == nullptr;
     }