Buildsystem/Core: Adjust MySQL headers on relevant files to use simplified #include <mysql.h> instead of <mysql/mysql.h>

+ add support for compiling under MacOSX (thanks to elegos for the research)
NOTE: G3D requires a redefinition-hack under OSX, please see wiki for this info (dep-sources will not be changed)

--HG--
branch : trunk

src/server/shared/Database/MySQLConnection.cpp

@@ -19,6 +19,9 @@
 
 #include "Common.h"
 
+#ifdef _WIN32
+  #include <winsock2.h>
+#endif
 #include <mysql.h>
 
 #include "DatabaseEnv.h"