Compile Error fix

[smaTc]

added namespace std, so it compiles

[xLAva]

Hi!
Thx for your pull request.
Can you just maybe give a bit more information.
For what compiler does this fix a compile issue?

Windows, Linux?
gcc, clang, VS2013, VS2015?

[smaTc]

Hey,
Linux(Ubuntu 16.04), GCC. While building I got a compiler error stating a variable was not declared in this scope. Using the namespace fixed it. Build finished and the game is running fine.