Synchronized source file headers (#3212)

* Alphabetically sorted includes.
* Updated copyright and license text to match across all files.
* Removed pragma once define in header files in lieu of ifdef guards.

src/map/mapreg.cpp

@@ -1,4 +1,4 @@
-// Copyright (c) Athena Dev Teams - Licensed under GNU GPL
+// Copyright (c) rAthena Dev Teams - Licensed under GNU GPL
 // For more information, see LICENCE in the main folder
 
 #include "mapreg.hpp"